Yellow signifies mental and spiritual enlightenment, vitality, and hope. Together this blended stone presents the wearer with a gem that is symbolic of spirituality, steadfast loyalty, and a zest for life. Ammonites are named after the Egyptian god Ammon, who is often depicted with rams' horns behind each ear.
Ammonites were predatory, squid-like creatures that lived inside coil-shaped shells. Ammonites first appeared million years ago. They were prolific breeders, lived in schools, and are among the most abundant fossils found today. They went extinct with the dinosaurs 65 million years ago. Ammonite is a spiritual indication of harmony, dignity, and splendor. Ammonites give you a sense of beauty, seductive charm, and charisma.
It awakens interest in mysteries and releases mental obsessions. Ammonites are the ancient equivalent to the modern-day chambered Nautilus. These sea faring squids built a chambered shell in which they would pump air into the empty chambers and float at different levels of the ocean in search of food. This unique ability to float at different depths of the ocean is what inspired Jules Vern the famous science fiction writer to call the first submarine the Nautilus.
Apatite originates from the Greek word for "cheat". That unfair title was allegedly earned from apatite's possible confusion with other stones. It is a stone seldom found in jewelry stores and virtually unknown to the general public, is beloved by collectors for its many different colors and forms. The range of colors includes colorless, pink, yellow, green, blue and violet. With a hardness of 7, Aqua aura is quartz that is gold infused. It is created by heating quartz crystals to over F in a vacuum.
Once the right heat and vacuum is attained, chemically purified gold vapors are let into the chamber with the crystals. This bonds the gold to the lattice of the crystal, forming a permanent bond to the surface of the quartz, giving it an electric blue color. Though not created through a natural process, the synergy of the quartz and gold combine to bring about a new crystal of intense energy and power.
Aqua Aura is used by crystal healers and others to calm the emotions. It is a powerful stress reliever. It is also a strong energy for reducing or eliminating anger. It is said to help process emotional disturbances, grief, and traumas to a point where they are no longer stressful. Aqua Aura is called both a success stone and an abundance stone.
It is said to attract success to all who use or carry it. The gemstone Aquamarine is the modern March birthstone. Aquamarine is a member of the beryl family and ranges in color from an almost colorless pale blue to blue-green or teal. The most prized color is a deep-blue aqua color. It is 7. The most valuable aquamarines come from Brazil.
Since early times, aquamarine has been believed to endow the wearer with foresight, courage, and happiness. It is said to increase intelligence and make one youthful. As a healing stone, it is said to be effective as a treatment for anxiety and in the Middle Ages it was thought that aquamarine would reduce the effect of poisons.
A legend says that sailors wore aquamarine gemstones to keep them safe and prevent seasickness. It also signifies the making of new friends. Aventurine is a translucent to opaque variety of microcrystalline quartz. It contains small inclusions of shiny minerals which give the stone a sparkling effect.
Inclusions of mica will give a silverish sheen, while inclusions of hematite give a reddish or grayish sparkle. Aventurine ranges in color from green, peach, brown, blue and a creamy green. Besides its uses in jewelry, aventurine is also used for ornamental purposes like vases, bowls, and figurines. This mineral is often mistaken for amazonite or jade. It is interesting that the name for the stone is derived from an accident.
Sometime during the 18th century, Venetian glass workers were preparing molten glass when copper filings accidentally fell into the batch producing a glass with sparkles. The name aventurine comes from the Italian "a ventura," which means"by chance". Aventurine has been used as a lucky talisman and is a popular stone for gamblers. Legends say that it is an all-purpose healer, used to reduce stress, develop confidence, imagination and improve prosperity.
A legend from ancient Tibet says that aventurine was used to improve nearsightedness and to increase the wearer's creativity. Many believe that aventurine has the capacity to calm a troubled spirit and bring about inner peace. Azurite is an intense deep blue color. For thousands of years this stone has been used in jewelry and ornamental objects. During the Middle Ages and Renaissance it was ground into pigment for use in paint and eye shadow.
Azurite was sacred to the Egyptians who believed it was an aid to spiritual communication. Many believe that this stone helps to reduce anger and to increase psychic awareness. It is also thought to reduce abnormal cell growth, promote wisdom, and is used as an aid to relieve the pain of rheumatism.
Bumblebee Japer, is found on the island of Bali, near the town of Garut, Indonesia. It is collected by locals near hot vents of an active volcano called Mount Papandayan. The peak is around 8, feet high, which is one of the tallest volcanoes in Indonesia. Bumblebee Jasper cabochons are not really a chalcedony, jasper or agate, but are actually a mixture of volcano lava and sediment. The colorful Bumblebee contain gypsum, sulfur, hematite and a small amount of orpiment.
Metaphysical Properties: Bumblebee Jasper cabochons are said to help your concentration and inspiration by helping you focus better. This belief made the stone a popular talisman among the Muslims. This gemstone is used for clear thinking and to balance creativity and mental processing.
Chalcedony is derived from the name of the ancient Greek seaport Chalkedon in Asia Minor. Inthe 3rd or 4thcentury A. Chalcedony, which is found worldwide, is the name for a group of stones made of a microcrystalline variety of quartz, which means the quartz crystals are too small to be seen without high magnification. In jewelry usage, the name Chalcedony is usually applied only to the light blue translucent and waxy form.
Other stones in this group are know as agate, jasper, bloodstone, tiger's eye, chrysocolla, chrysoprase, onyx, sardonyx, and carnelian. Chalcedony is found in almost every color. Native American Indians believed chalcedony was a sacred stone and used in the spiritual ceremonies of the tribe. It is thought to increase vitality, stamina, and endurance and to promote emotional balance and charity while relieving melancholy, fever, gallstones, and eye problems. It was once believed that someone seeing nocturnal phantoms took in disease though their eyes, but the "alkaline" content of chalcedony could remove it.
Charoite name is derived from the Charo River which is near where it was found in Russia in in the Murun mountains in Yakutia. This the only known location for this rare mineral. Charoite is so unusual looking with its chatoyancy and strange looking spirally strands of fibrous material that it is often mistaken for a synthetic.
It is used extensively in jewelry and as an ornamental stone carved into boxes, bookends and vases. It ranges from 5 - 6 on the Mohs scale. Charoite is said to enhance self-esteem, accelerate spiritual growth, and improve the ability to love.
Chinese Writing Stone was probably named because of the crystalline structure resembling the Chinese characters of the written language. It is a limestone matrix with andalusite crystals. It is also called Porphory. Colors range from a very dark gray or almost black to creamy white, both of which have a slight greenish cast. A dramatic looking stone, it is a on the Mohs scale. It is an excellent stone for dreaming, assisting one into a dream state and it is a stone of re-affirmation, re-alignment and re-commitment.
It helps one to adjust to change, accept responsibility and stimulate originality Back to Top. The gemstone Chrysocolla is often confused with turquoise. It is a copper bearing mineral found wherever copper deposits occur especially in areas of the southwestern USA, Chili, Zaire, Australia, France and England.
Eliat Stone is a variegated blue and green mixture of chrysocolla and other copper minerals found in the Gulf of Aqaba, near the northwestern end of the Red Sea". Pure chrysocolla is too soft for jewelry purposes but it is often found in quartz deposits which makes it hard enough to polish for cabochons.
It is often found mixed with malachite, turquoise and azurite. Pure chrysocolla is between 2. Said to aid creativity, female energy, communication,relieves ulcers and arthritis.
Chrysocolla is associated with tranquility and peace, intuition, patience, and unconditional love. It is thought to offer gentle and soothing qualities. Chrysoprase— was once used for spiritual protection and was said to be a victory stone. Chrysoprase is a natural green color gemstone from Queensland, Australia, and is often referred as Australian Jade.
Cinnabar is a red crystalline form of mercuric sulphide. In its natural state, it is a red crystalline solid. Sometimes, its red color is so bright that it is not found in any mineral, plant and animal on earth. It occurs in brilliant red or in red or brown amorphous masses. The Chinese and the Arabian alchemists used to extract mercury from it. Today, it is the only source of mercury and is found in rare localities.
Since of its red color, it was also used as a dye. The word 'Cinnabar' has been taken from the Persian for 'dragon's blood.
Psychologically, it represents the hardened habits and terrestrial marriages of the soul and spirit. Cinnabar is also a stone of repute in giving wearer long life.
The hardness of cinnabar is 2 to 2. Citrine — The birthstone for November and the top selling gem in the yellow to orange color. Citrine's color is thought to radiate positive energy. It is known as the 'success stone', since it is believed to promote prosperity and abundance, especially in situations involving business.
Citrine has actually earned the nickname of 'the merchant's stone', owing to the fact that many businesses will keep citrine in their cash registers for good fortune. According to legend, citrine is able dissipate negative energy. It is also thought to generate stability in life and be good for general protection. The name is derived from the French word citron, meaning "lemon".
Diamonds are very rare gemstones. Many of them are clear, but they may have colors. There are natural and synthetic diamonds. Diamond is the hardest natural material known, where hardness is defined as resistance to scratching and is graded between 1 softest and 10 hardest using the Mohs scale of mineral hardness. Diamond has a hardness of 10 hardest on this scale. Diamonds are actually made of pure carbon. In fact, the only thing hard enough to cut a diamond is another diamond.
Diamonds are made deep in the earth, where there is an intense amount of pressure and heat that makes the diamond form. The name diamond is derived from the ancient Greek, "unalterable" and "unbreakable, however, diamonds are thought to have been first recognized and mined in India for at least 3, years.
The popularity of diamonds has risen since the 19th century because of increased supply, improved cutting and polishing techniques, growth in the world economy, and innovative and successful advertising campaigns. The hardness of diamonds contributes to its suitability as a gemstone. Because it can only be scratched by other diamonds, it maintains its polish extremely well. Unlike many other gems, it is well-suited to daily wear because of its resistance to scratching—perhaps contributing to its popularity as the preferred gem in engagement or wedding rings, which are often worn every day.
The mined rough diamonds are converted into gems through a multi-step process called "cutting". Diamonds are extremely hard, but also brittle and can be split up by a single blow. Therefore, the diamond cutting is traditionally considered as a delicate procedure requiring skills, scientific knowledge, tools and experience. Its final goal is to produce a facetted jewel where the specific angles between the facets would optimize the diamond luster, which is the dispersion of white light, whereas the number and area of facets would determine the weight of the final product.
Several possible shapes are considered, but the final decision is often determined not only by scientific, but also practical considerations.
For example the diamond might be intended for display or for wear, in a ring or a necklace, singled or surrounded by other gems of certain color and shape. Because of its unique brilliance and superior hardness, diamond has come to symbolize eternal love. The tradition began in the 15th century, when Archduke Maximilian of Austria sealed his engagement to Mary of Burgundy with a diamond ring.
Diamonds symbolize brilliance, constancy, excellence, innocence, invulnerable faith, joy, life, love and purity. Druzy Quartz also spelled as Drusy - Druzy is tiny quartz crystals that form within or on the surface of other stones.
When ground water carrying dissolved silica is forced into a porous area of the rock, rapid cooling often occurs, causing the formation of tiny crystals on the surfaces or in cavities of the rock.
The clear crystals often form on top of previously deposited minerals. This is called a druzy. Titanium druzy is agate druzy that has been coated with titanium in a vacuum chamber. This produces a permanent metal coating in spectacular colors. Usually Druzy Quartz takes the host stone's color. Druzy Quarts is said to aid in balancing and increasing energy. Since ages it has been used to diagnose disease and is believed to enhance natural extrasensory perception abilities.
Dioptase - Dioptase is very fragile and specimens must be handled with great care. Dioptase was used to highlight the edges of the eyes on three Pre-Pottery Neolithic lime plaster statues that date back to about BC. Dioptase is an uncommon mineral found mostly in desert regions. Dioptase is popular with mineral collectors and it is occasionally cut into small emerald-like gems. Although Diopside and Dioptase seem like they might be closely related, they are really far apart. One is a hydrated secondary copper mineral while the other is a magnesium iron mineral found in metamorphic rocks.
Emerald is the only stone, besides Topaz, that is listed as in all of the ancient birthstone tables. Emerald is the name given the green variety of beryl and ranges between 7.
Top quality emeralds are a deep grass green with a slightly bluish cast, but many lesser quality stones are lighter shades of green and can have a more yellowish tone. Emeralds are found in many countries, but Columbia and Brazil are the major producers and Columbia is recognized as the source for the finest stones.
Because emeralds usually contain many cracks, fissures, and inclusions, the majority of these stones are "oiled". This means that they are immersed in oil which reduces the visibility of the inclusions, and also improves the clarity. Oiling is almost universal and because it is so common today, it is not considered necessary to disclose this fact Emeralds are brittle stones and care should be taken when wearing or cleaning them.
They should never be immersed in an ultrasonic or subjected to steam cleaning. Emeralds were used as amulets to ward off epilepsy in children and thought to cure diseases of the eye. Folklore suggests that these stones will improve memory, intelligence, and enhance clairvoyance thus helping to predict future events. They are also worn to enhance love and contentment. Cleopatra prized emeralds above all other gems. Fluorite, is a soft stone with a hardness rating of 4 on Mohs scale. Ancient Romans believed that drinking alcoholic beverages from vessels carved of fluorite prevented drunkenness.
Most specimens of fluorite have a single color, but a significant percentage of fluorites have multiple colors and the colors are arranged in bands or zones. Fluorite is frequently fluorescent under ultraviolet light UV and, like its normal light colors, its fluorescent colors are extremely variable. Typically it fluoresces blue but other fluorescent colors include yellow, green, red, white and purple.
The origin of the word fluorite comes from the Latin verb to flow and reflects today's use of fluorite as a flux in steel and aluminum processing. Fluorite is also used in the manufacture of high-octane fuels and in the production of hydrofluoric acid. It is said to intensify emotions and moods — making them obvious.
It also is said to aid freedom of choice, bring ideas, and a quick intellectual grasp. It is also said to be good for the skin, nerves, and bones. It was originally referred to as fluorspar by miners and is still called that today. Fluorite is also used as a source of fluorine for fluorinated water.
Many people believe it has a calming effect on the body. During the eighteenth century it was ground into powder and mixed with water to treat kidney disease. Fordite, is also known as Motor Agate. The original layered automotive paint slag was made by the now extinct practice of hand spray-painting cars.
The over sprayed paint in the painting bays gradually built up on the tracks and skids that the car frames were painted on. Over time, many colorful layers built up there. These layers were hardened repeatedly in the ovens that the car bodies went into to cure the paint.
Some of these deeper layers were even baked times. Eventually, the paint build-up would become obstructing, or too thick and heavy, and had to be removed. The old factory methods that created this incredible material are long gone.
Garnet occurs in every color except blue and most varieties are named for their color. As far back as BC Egyptians along the Nile worked garnet into beads and inlays.
Rhodolite is a purplish red, Hessonite is the name for an orange, cinnamon, or pinkish variety. Tsavorite is the name given to dark green grossularite. Uvarovite and Demantoid are also green varieties. Pyrope garnets are purplish red, orangy red, crimson, or dark red.
Garnets range from a 7. Garnet's powers include healing, strength, and protection and it is often worn to relieve inflammations of the skin. It is also believed to regulate the heart and blood flow and aid in curing depression. In earlier times, garnets were exchanged as gifts between friends to demonstrate their affection for each other and to insure that they meet again.
North American Indians used red garnets at bullets, believing they would seek blood and inflict a deadlier wound. Garnets were thought to stop bleeding, cure inflammatory diseases, and smooth discord.
Gaspeite is a relatively rare mineral, found only in a few localities. Its light green, almost apple green color is quite unique and some varieties are almost a neon green. It may contain brownish patches which may give it a distinctive character. Gaspeite is found around nickel sulfide deposits and is named for the locality of Gaspe Peninsula, Quebec, Canada where it was originally found.
Sources are Canada and Western Australia. Hardness is 4. Hematite is a very common mineral consisting of iron oxide. Its color ranges from steel gray to almost black, brown to reddish brown, or red. Hematite is harder than pure iron, but it is much more brittle. The name hematite is derived from the Greek word haimatites for blood. It is the state mineral of Alabama, USA where approximately million tons were mined between l and Hematite iron ore is a very common mineral on Earth and it also occurs everywhere on the planet Mars - where it is responsible for the planet's distinctive red color.
An important pigment known as "red ochre" it was used in cave paintings and paint pigment. Hemimorphite forms in oxidized zinc deposits and always occurs in clusters of radiating, acicular crystals. Hemimorphite is in the form of bladed crystal.
The crystals are generally elongated and flat. When heated, the stone readily becomes frosted. When hot, the coating is yellow but after cooling it turns white. It even fluoresces a bright orange in long-wave ultraviolet and white in short-wave ultraviolet. It is a wide believe of Hemimorphite being a help for one to attain a positive self-image including self-esteem and self-respect.
It also assists in the personal growth of a person on all levels. The stone brings joy and creativity. For healing, it is an excellent stone.
It relieves pain, cures ulcers, blood diseases and cellular disease or disorder. Sometimes it is also used as protection stone from malice and poisoning. Iolite— from the Greek word meaning violet.
Iolite shows different colors from different viewing angles and can appear gray, violet, or yellow. Iolite is known as the gemstone of clear vision. Viking navigators found their way on cloudy days by viewing the sky through a thin piece of Iolite which acted like a polarizing filter. Jade is the term applied to forms of jadeite and nephrite. These minerals are similar in appearance and a distinction between the two often was not made.
But, because of its more intense color and translucency, jadeite now brings higher prices and is thought to be the true jade. The most valuable form of jade is known as Imperial jade and comes from Myanmar, it is an emerald green color. Jades also appear in mottled green and white, and the rarer colors of yellow, pink, purple, and black.
The range of greens are light to dark, creamy, grayish, and also white. Jade is also found in Mexico, and Central and South America. Because of its smooth even texture, jade has long been a preferred material for carving and is usually cut into cabochons for jewelry.
The color of the stone is the most important factor but translucency and texture are important criteria determining price. Jasper is an opaque and fine grained variety of Chalcedony. It often contains organic material and mineral oxides which give it interesting patterns, bands and colors. Many of these patterns resemble landscapes with mountains and valleys, thus the name "picture" is part of the name of many well know jaspers.
Jasper was a favorite gem in ancient times and is referenced in Greek, Hebrew, Assyrian and Latin literature. The high water content of the magma makes it possible for the crystals to grow quickly, so pegmatite crystals are often large. Of course, this is important for gem specimens! When the pegmatite magma is rich in beryllium, crystals of beryl form. If magmas are rich in boron, tourmaline will crystallize.
You should note that beryllium and boron are extremely rare elements in most rocks and it is only because the above process efficiently concentrates these unusual elements that crystallization of boron and beryllium-rich minerals can occur. More information on pegmatites.
This movie shows formation of crystals such as emeralds and tourmaline in pegmatite bodies associated with cooling intrusive magmatic rocks Here is some additional information about this movie. Magmatic gems Some gems crystallize in magmas or in gas bubbles holes in volcanic rocks. Examples include: zircon , topaz , ruby , etc. This movie shows formation of crystals such as ruby or zircon pink crystals and topaz in open cavities e. Metamorphic gems Metamorphic rocks are rocks changed by heat, pressure, and interaction with solutions.
There are a number of types of metamorphic environments: Plate tectonics creates metamorphic environments characterized by high temperature and high pressure - produce jadeite jade. In extremely rare cases, pressures in metamorphic rocks may be high enough that diamonds form. Regionally metamorphosed rocks: large volumes of rock that are buried and changed in response to increases in pressure and temperature. Minerals found in these rocks might include gems such as garnet and cordierite.
This movie shows metamorphism of rocks resulting from continent-continent collision associated with a subduction zone. Note the formation of large crustals such as garnet in the deformed, heated zone. This movies illustrates the process of contact metamorphism. This is the process by which the minerals in rocks change in response to proximity to a hot intrusive body.
For example, a limestone intruded by a magma undergoes significant change in crystal size, mineral content, and chemistry due to addition of solutions released from the cooling magma.
These rocks contain gems such as garnet. Gems formed in the mantle The most abundant upper mantle mineral is olivine peridot. Slabs of mantle material are brought to the surface through tectonic activity and volcanism. Deep mantle gems. Quartz occurs in a variety of forms in igneous, sedimentary, and metamorphic rocks. Silica forms both crystalline quartz and several amorphous and microcrystalline varieties. Pure crystalline quartz is offend called " rock crystal " and is used for many ornamental and commercial products and is possibly the most abundant gem variety Figure Crystalline quartz, including quartz varieties of amethyst and citrine, can form in open cavities igneous and sedimentary settings, covering walls in fissures with crystal masses Figure Sedimentary varieties of the "quartz family" that do not display obvious crystals include chalcedony, agate, and chert.
Chalcedony is a microcrystalline form of quartz Figure Chalcedony is typically translucent that often displays banding or unusual botryoidal shapes. It is typically pale whitish to gray, or light blue in color. Agate is a hard variety of chalcedony that is typically banded in appearance Figure The banding is due to impurities typically iron and other metal oxides.
Agate is durable and is frequently used in cabochon jewelry settings or ornamental objects. It can hold a high, durable polish. Chert is a name for a hard sedimentary rock composed of microcrystalline quartz colored by mineral impurities Figure Some dull-colored varieties of chert are called " flint.
Figure shows flint points from southwestern Ohio. Chert forms from the precipitation of silica in lakebeds and in the deep ocean. Sources of silica include volcanic ash and siliceous skeletal remains of microscopic organisms diatoms and radiolarians , and spicules of some siliceous sponges.
Siliceous ooze dominates sediments in many places in the cold depths of open ocean basins. Exposed layered bed of oceanic siliceous deposits are called "ribbon chert" Figure is an example exposed on Mt.
Diablo in California. Red varieties of chert are called " jasper " - a variety often used in making polished cabochons for jewelry. Chert occurs in practically any color; most color in chert are a result of traces of iron minerals hematite is red, gray to black; limonite is yellow, orange to brown Figure and Clays, metallic oxides copper, manganese, etc.
Chert is often shattered into angular fragments that can be reworked and re cemented into " chert breccia " Figure Note that most chert you find has been recrystallized from a softer unconsolidated silica-rich sediment or sedimentary rock, and much of what is used in jewelry making has been altered to a metamorphic variety, called metachert. Classification of non-clastic sediments and sedimentary rocks. Coral and most shells consist of calcite. Pearl and mother-of-pearl are aragonite.
Smithsonite greenish and Azurite blue. Nodules, Geodes and Concretions Many sedimentary rock formation contain "nodules. Another term for nodule is " concretion " - a rounded or oval shaped mass weathering from sedimentary rock.
Examples include in pyrite nodules in shale or coal beds, chert nodules in limestone, and limestone concretions in shale. Nodules form in a variety of ways. Nodules sometime form around decaying organic matter deposited in muddy or limey sediments. The gases released from decaying material release gases and compounds that can drive chemical reactions, causing minerals to precipitate in the microscopic pore-space in the sediments surrounding the organic matter.
Cavities filled with gases or water can become sites where crystals can form. A geode is a nodule that has a hollow space inside filled with crystals Figures and ; both geodes are from Kentucky.
Common minerals inside geodes are usually varieties of quartz clear crystal and amethyst , chalcedony, agate, calcite, dolomite, barite, fluorite, pyrite, and gypsum. Geodes can sometime have rare and unusual minerals as well. Sometimes the space can be completely filled, such as the agate nodule shown in Figure Septarian nodules are "limestone concretions" that have angular crack or cavities called septa within that are filled with crystals, typically calcite Figure Nodules and concretions commonly occur in discontinuous layers or with beds of sedimentary rocks.
They can have unusual shapes, such as nodules that form in sandstone Figure These features are secondary structures that often cut through laminations and bedding in the surrounding sediments. They also fill in voids and bubbles formed in lava flows. Some volcanic ash beds host abundant geodes. An oolite is a sedimentary rock formed of spherical grains conposed of concentric layers, called ooids egg stones.
Once an ooid grows beyond 2 mm it is called a pisolite Figure Ooids and pisolites are a commonly composed of calcite or hematite, but can form from other minerals. If cyanobacteria or other microbial life is involved, they are called oncolites. Ooids, pisolites, and oncolites form as fragments of rock small shells or other organic matter roll around in agitated water, such as in a shallow lake or shallow marine embayments.
Over time, they pisolites or oncolites grow larger and larger until they cannot move and become buried. Geode with quartz, barite, and fluorite. Organic gem materials and deposits Some fossil materials make exceptional pieces for displays and adornment.
They are especially coveted by people who are fascinated with Earth history. Natural history museums around the world are filled with fossil collections, and exceptional discoveries are on display, both in the paleontology collections and gemstone sections. A fossil is a remnant or trace of an organism of a some earlier geologic age, such as a skeleton, shell, or leaf imprint, embedded and preserved in the earth's crust.
Fossilization involves processes that turn plant or animal remains to stone. A few "gems" form as organic accumulations such as when plant, shell, teeth, or bone material collects. Although fossils are generally rare, they can occur in abundance in some sedimentary environments Figure Gem materials from fossils include amber, jet, " nacre" ornamental mother-of-pearl, and fossil pearls themselves.
Some small fossils make attractive adornment as well. Fossil wood is perhaps the most abundant fossil, some of which makes exceptionally colorful and durable for cutting and polishing. Small pieces are common, but whole redwood-sized trees are found in "fossil forest" beds, such as those exposed in Petrified Forest National Park in Arizona Figure The ancient trees Triassic age was buried in sediments laden with volcanic ash that supplied the silica and other minerals that replaced the wood.
In ocean sediments, the shells of ancient mollusks called ammonites are related to present day squid and octopus Figure They have spiral or straight conical shells composed of mother-of-pearl. Ammonites lived in the Mesozoic era and vanished along with all dinosaurs about 65 million years ago. Coral, both living and fossil, is used in jewelry as well. Other "organic gems" include, mammoth ivory, fossil invertebrates including sand dollars, brachiopods, trilobites, etc.
Few of these organic materials are very durable, but they can become hardened by recrystallization and mineral replacement processes. Fossil dinosaur bone and coprolite fossil dung are popular gem cutting material. Amber is fossil tree resin that oozes from trees.
When buried it can harden into a transparent gem Figure Coal is fossil plant material.
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