Agates:  Agate is a "chalcedony" which is one of the many varieties of quartz. It is scientifically classified as a cryptocystalline or microcrystalline quartz.  Agates come in many different forms.  The main conditions necessary for agate formation are the presence of silica from devitrified volcanic ash, water from rainfall or ground sources, and manganese, iron and other mineral oxides that form the bands and inclusions.  Also see individual listings, BLUE LACE AGATE, MOSS AGATE and TREE AGATE.
Amber:  Formation of amber goes back millions of years ago - up to 300 million years - when, certain tree resin hardened and fossilized over a long period of time.  Amber comes in shades from Yellow to Honey to Reddish Brown, often with Black veins or fossil residue inside.  Whatever got trapped in the tree resin, got preserved in exactly the same shape to the very finest detail - droplets of air, water, pieces of leaves, flowers, wood from ancients forests, even small living organisms such as insects are still found in amber.  The biggest source of amber comes from Northern Europe's Baltic Sea region.  Used in jewelry making in Europe for ages, as well as a form of currency and even a medicinal stone.  One check for authenticity is to touch a hot needle to the stone, the resulting smoke should smell of pine woods.
Amethyst:  Translucent Purple crystal from Africa said to bring good luck and protect against drunkenness.  Hues range from Lavender to deep Regal Purple.
Amethyst Quartz:  see CAPE AMETHYST and LAVENDER AMETHYST.
Ammolite:   Ammolite is the modern-day gemstone of ammonite, and because every single gemstone is a fossil, it is regarded as the rarest gem on earth.  Rare, gem-quality ammolite appears similar to Black opal, showing different color combinations when the stone is viewed from different angles. The most common colors range from Yellows, Oranges to Reds and Greens. The Blues are more rare and hence more expensive.
Amazonite:  A translucent, Pearly, Pink or pale azure Blue crystalline stone with a surface resembling finely cracked marble.
Apatite:  Translucent Teal Green faceted or cabachon gem.
Apricot Moonstone:  Peach/Apricot colored moonstone endemic to India.
Aquamarine:  Watery Blue translucent gem used as a talisman for sailors.
Aventurine:  Somewhat turbid bright Green stone consisting mainly of quartz with Greenish Brown flakes (sometimes falsely referred to as Indian Jade).
Aventurine Feldspar:  see SUNSTONE.
Azurite:  An azure Blue color that is oftentimes found with malachite.  Azurite and Malachite are basic carbonates of copper.

Baroque Pearls:  Large oddly shaped pearls that are usually used as art pieces.
Beryl:  Beryl is a family of gemstones that includes: Green, Aquamarine, emerald, heliodor (Pink), morganite (Yellow), and Red.
Biwa Pearls:  A Biwa pearl is a pearl that comes from a specific region in Lake Biwa, Japan.  These pearls were easily distinguished by their smooth, luminous skin.  Now the term is used to refer to nearly all such pearls.
Black Onyx:  Sometimes referred to as Black agate, it actually is a form of banded agate containing layers of varying colors.  The contrast between layers makes it ideal for cameos.  Less expensive black jade and obsidian are sometimes used in its place.
Black Star or Star Diopside:  Black stone with a moving "Star" or "Cross".
Blister Pearls:  see MABE PEARL.
Bloodstone:  Dark Green opaque stone with Red spotting.
Blue Lace Agate:  Light Blue translucent stone with White or Milky banding.
Blue Topaz:  Faceted bright Sky Blue crystal topaz.

Cape Amethyst or Amethyst Quartz:  Translucent light to medium Purple stone with White banding.  This is actually a rough form of amethyst layered or striped with milky quartz.
Carnelian:  Dark Red to Orange colored agate thought to soften anger.  The Orange variety frequently has areas of lighter and darker Orange, giving it a banded or less uniform look.
Cat's Eye:  Gem with a natural line breaking and moving across the stone.
Chalcedony:  Refers to the family of quartz that contains tiny crystals.  Examples include:  onyx, agate and chrysoprase.  Often used to refer to a solid color, translucent, light Blue stone.  Watery Blue agate gem once used for cameos.
Charoite:  The swirling Purples of Charoite resemble the eddys and rushing waters in a fast moving stream.  The colors range from deep Purple to pale Lavender inter-spiced with White.  Charoite is composed of: Hydrated Sodium, Calcium, Barium Strontium, Silicate Hydroxide Fluoride.  Charoite is found only along the Chara River Valley in a very remote area of East Central Siberia. The only source for these gems is located about 325 miles NE of the northern tip of Lake Baikal. It is in the Chara Region (State) and is near the Region's northern border.
Chatoyancy:  The appearance of a line or a star within a gemstone when it is viewed in a certain light and at an angle.  Star sapphires and cat's eye chrysoberyl or tiger's eye stones exhibit this quality.  These stones are always cut as cabochons to bring out this quality.
Citrine:  Golden "Citrus" colored translucent faceted gem, sometimes is called topaz quartz.
Clear Quartz or Rock Crystal:  A colorless transparent stone.
Clinochlore:   Forms from the metamorphic and hydrothermal alterations of other iron and magnesium silicate minerals.
Coral:  Actually the skeletal remains of marine organisms, coral has been prized since 3,000 B.C.  The most valued pieces have a uniform bright Red color, though Pink and Salmon colors are also popular.

Emerald:  Faceted deep Green transparent gem from India.

Fancy Jasper:  An opaque multi-colored stone.  Colors are muted and range from Green-Blue to Pinkish to Orange-Yellow frequently in the same stone.
Fluorite:  A transparent stone with Green and Purple with clear areas or bands.
Fossil:  Fossilized crinoid with a Black, White and Pink spotted appearance.

Garnet:  A family of crystals named for its resemblance to Red pomegranate seeds.  Usually Reddish-Brown, but can range from true Red to Blackish Red.  Deep Red fiery translucent stone are from India.
Gaspeite:  Light Green to Apple Green in color.  Named for the Gaspe Peninsula in Quebec where it was originally found. The color comes from the fact that it is found around nickel sulfides.  Occurs in Rhombohedron and scalenohedrons, as well as ball shaped aggregates.  More recently it has been rediscovered for its lapidary use and found a place in the semi-precious stone market.  Cut into cabochons and set in sterling silver, it is often coupled with other stones such as AZURITE and SUGILITE for a stunning contrast and look.
Gray Moonstone:  Transparent moonstone that is Gray in appearance.

Hawk's Eye:  Chatoyancy, appearing in these varieties of quartz, is caused by fibrous inclusions of crocidolite.  Blue-Red or Bluish in appearance.
Hematite:  A type of iron oxide with a Blackish-Gray metallic luster, sometimes has a Brownish Red appearance.  Used in the ancient times as a shiny surface for mirrors.
Howlite:  Opaque snow White stone with Black veins and similar appearance to marble.  In its natural form, howlite's White nodules resemble cauliflower.  This opaque White stone with Gray or Brown veins is porous, so it takes dye easily and is frequently used to simulate more expensive semiprecious stones.

Iolite:  Translucent "Greasy" Violet Blue stone from India.
Iron Tiger's Eye:  Brown Tiger's Eye with an excess of iron deposits that give it Gold, Red and Gray fiber highlights.

Jade:  Jade is applied to jadeite and nephrite.  Jadeite is composed of microscopic interlocking crystals that produce a very tough material.  Nephrite is actually not a mineral, but a variety of the mineral actinolite.  The nephrite variety is composed of fibrous crystals inter-twinned in a tough compact mass.  The emerald green jade called Imperial Jade is colored by chromium.  The presence of iron produces other Greens and Brown, and manganese the Violet colors.  Nephrite is usually only Green and creamy White, while jadeite can have the full range of jade's colors.  Jade is an extremely tough stone.  Besides jewelry it is used in gem carving.
Jade "Chinese":  Pea soup colored jade used as a cure for kidney disease in ancient times.
Jasper:  Jasper is a catch-all term applied to opaque, colored chalcedonies.  Often jasper displays no pattern, but the body coloration is usually heavy and rich, in shades of Brown, Red, Green and Yellow.  The material is dense and hard and takes a high polish.  It has been used and admired throughout the ages for jewelry, ornaments and small sculptures.
Jet:  Shiny Black dense coal or lignite.  Most varieties in costume jewelry are made of glass.  Once used to carve amulets, it was also popular in Victorian England.

Lapis Lazuli:  Lapis lazuli or lapis for short is mostly lazurite but commonly contains pyrite and calcite.  The name means blue rock and is always a brilliant Blue with Violet or Greenish tints.  Pyrite crystals sometimes give it a mottled look.  The rich Blue color is due to the sulfur that is inherent in the structure of lazurite.  In a piece of jewelry the small crystals of pyrite found in lapis blend with the setting, looking like gold in a gold setting and silver in a silver setting, giving the stone a personality all its own.  Most lapis looks in the market are dyed howlites.  Denim lapis is a cheaper form with a faded Blue color.
Labradorite or Spectrolite:  Part of the moonstone family with lustrous metallic tints of Blue and Green peacock shades.
Lavender Amethyst:  The deep Purple variety is the most expensive, hence it is used primarily in fine jewelry.
The most highly prized of quartz stones, it gets its name from the Greek word "not drunken" because it was thought to prevent drunkenness.
Lemon Chrysoprase:  Sunny Lemon opaque gem in the chalcedony family.
Lodalite:  Transparent Clear crystal with Pink to Gray scenic moonscape markings.

Mabe Pearl:  Cream and Rose colored Japanese developed cultured pearl also called blister pearls.
Malachite:  Lite Green to Emerald Green concentric rings and parallel lines throughout to create a "Silky" appearance.  This stone is used in jewelry and for tabletops and decorative objects.  Major sources are the Ural Mountains, Africa and Chile.
Marcasite:  These shiny crystals of iron pyrite first gained prominence in the 18th century when they were used as imitation diamonds.  It usually has a deep Gray or Black color and often has tiny Yellow metallic flecks.
Moonstone:  A variety of feldspar with a soft pearly sheen in delicate Pinks, Blues, Greens and Whites.
Moss Agate:  Actually in the chalcedony family.  Semi-transparent to opaque, mostly a variety of Green tones with a little White or clear.
Mother Of Pearl:  Comes from the inner layer of mollusk shells and has an iridescent White or Cream color.

Natural Carnelian:  see CARNELIAN.
Natural Onyx:  A semi-translucent to opaque, light colored stone with some banding.  Found in varying degrees of Yellowish-White, pale Greenish-White, and Gray.

Obsidian:  A natural glass that forms from volcanic activity.  Because it rapidly cools when exposed to air, it forms without crystals.  The most common color is Black, but Grey and Brown also occur.  Rarely, colors such as Red, Blue, and Green may also be found, and are the most expensive on the market.  Inclusions may add colors to it such as Gold, or Silver sheen, velvet, or a rainbow affect.  Some inclusions could be bubbles or crystals creating a random pattern such as snowflake.  Pebbles of lava that rapidly cooled are called Apache Tears.
Onyx:  see individual listings, BLACK ONYX, NATURAL ONYX and WHITE ONYX.
Opal:  Opal is considered a mineraloid because its structure is not truly crystalline.  It is formed of acid silicic, SiO2, and water, usually in porous volcanic stone.  Although there is no crystal structure, (meaning a regular arrangement of atoms) opal does possess a structure nonetheless.  Random chains of silicon and oxygen are packed into extraordinarily tiny spheres.  These spheres in most opals are irregular in size and inconsistent in concentration.  Yet in precious opal, there are many organized pockets of the spheres.  These pockets contain spheres of approximately equal size and have a regular concentration, or structure, of the spheres.  This has the effect of diffracting light at various wavelengths, creating colors.  Each pocket produces a different color, with a different intensity depending on the angle from which a viewer sees it.  Thus, the beautiful flashes of color that opal is famous for.

Paua Shell:  New Zealand abalone shell with intense Green, Blue and Pinks.
Pearl:  Creamy cultured pearl used for more than 6000 years as adornment.
Peridot:  Lime Green translucent stone.
Petersite:  Similar in appearance to Hawk's eye or Tiger's eye.  Chatoyancy, appearing in these varieties of quartz is caused by fibrous inclusions.  They are generally cut en cabochon, but is often cut into round pieces for necklaces and pendants.  A Golden Yellow reflection on a Brown stone is called tiger's eye.  If the stone is Blue-Grey or Bluish, it's colored by crocidolite, and is known as hawk's-eye.  A darker Brown, or Mahogany colored stone is known as bull's-eye or ox-eye.
Petrified Wood:  Actual pieces of prehistoric wood that became organic stone through thousands of years of freezing, thawing, drying, etc.  Usually Brown and Black, it often contains tree rings and bark.
Picture Jasper:  A Tan, opaque stone with medium and dark Brown patches that make the "picture".
Pietersite:  Known as the tempest stone it has combinations of Golden Brown and deep Blue-Gray colors with iridescent flashes of chatoyance.
Poppy Jasper:  Opaque with lots of autumn colors- brick Red, Whites, Browns, and Blacks.
Pyrite:  Blackstone with Gold pyrite flecks throughout.  Pyrite is also referred to as "Fool's Gold".

Quartz:  see individual listings, CLEAR QUARTZ, ROSE QUARTZ, SMOKEY QUARTZ, and WHITE QUARTZ.

Rainbow Moonstone:  Moonstone with a Blue and Pink opalescence.
Red Jasper:  An opaque, mostly a rusty colored than a brick Red stone, sometimes with a few dark veins running
through it.
Red Tiger's Eye:  Tiger's eye that is Red.
Rhodochrosite:  Opaque light Pink raspberry colored stone with thin White to Creamy-Pink veins or banding.
Rhodonite:  Medium Pink to kind of dusty Rose, often with Black or Gray inclusions.
Rock Crystal:  see CLEAR QUARTZ.
Rose Quartz:  Pink translucent crystal gem also referred to as the love or heart stone.
Ruby:  Warm Pink opaque ruby commonly found with inclusions that are not indicative of low quality, but show that the gem is natural.
Rutilated Quartz:  Clear quartz crystal with strands of Gold fibers.

Seraphanite (seraphinite):  This is a gemmy variety of clinochlore, a mineral of the chlorite group. Seraphanite originates from the Lake Baykal region of Siberia. These rare gemstones are primarily a deep Green color, with feathery inclusions of Silver-colored iridescent formations creating intricate chatoyant patterns.  The crystalline structure is monoclinic.
Serpentine:  Serpentine is found in many metamorphic and weather igneous rocks.  Most rocks that have a Greenish color probably contain serpentine in some amount.  The serpentine along with other material make for a beautiful patterns in the stone.  Serpentine can be an attractive Green stone that takes a nice polish and is suitable for carving.  It has been used as a substitute for jade and is sometimes difficult to distinguish from jade, a testament to the beauty of finer serpentine material.  Non-fiberous serpentine is not a cancer concern.  Asbestos serpentines should be kept in closed clear containers, but makes an attractive specimen.  Sometimes with a Golden color as the name chrysotile in greek means golden fibers.
Smokey Quartz:  A Brown transparent stone.  Ranges in color from very slightly Brown to dark-like root beer.
Smokey Topaz:  Translucent Cola colored topaz.
Snow Quartz:  see WHITE QUARTZ.
Snowflake Obsidian:  Black opaque stone with Gray flowering formations.
Sodalite:  A common opaque stone; its Blue color resembles lapis lazuli (also available in Mauve, Yellow-Green, Pink and Purple).  Grayish-White mottling is found in lower grades.  Has varying degrees of White veining (calcite) and occasionally a fleck or two of pyrite.  Its name reflects its sodium content.
Spectrolite:  see LABRADORITE.
Star Diopside:  see BLACK STAR.
Sugilite:  Sugilite is a stone of fairly recent discovery.  It does not form well shaped crystals but is usually massive; therefore, it is used as a cabachon for jewelry.  The polished stones are mostly opaque with an almost waxy luster and a deep Reddish Purple color.  It can be very dark, almost Black, to a nice pale Pinkish mauve.  It may have Black, swirly lines and spots of Yellow.
Sunstone or Aventurine Feldspar:  Sunstone is a member of the feldspar group of minerals and is closely related to Moonstone.  It is formed and crystallized in a lava flow. Sunstones range in color from water clear through pale Yellow, soft Pink, and blood Red to deep Blue and Green.  Some of the deeper colored stones have bands of varying color; a few stones show two different colors when viewed from different directions.  The color is caused by tiny crystals of copper within the stones which often results in "schiller" or shimmer that is usually a Peach color.  Sunstone is cut into cabochons or the deeper transparent colors may be faceted.

Tiger's Eye:  Opaque quartz stone with silky fibers or luster of Browns and Golds produced by iron, and is reverse when the stone is turned around.
Tourmaline:  Translucent gem from Sri Lanka with Watermelon shades of Pink and Green.
Tourmalated Quartz:  Clear quartz crystal with dark Green Tourmaline spears.
Turquoise:  Turquoise is a hydrous copper aluminum sulfate found in every color of Blue, Greenish Blue or deep Green.  The rich Blues are due to the abundance of copper while Green turquoise has more aluminum.

Unakite:  Pea Green opaque stone with shades of Orange and Pink throughout.

Variscite:  Variscite is a relatively rare phosphate mineral that is sometimes confused with turquoise.  It is usually Greener, it ranges from a beautiful apple Green to the more common pale Green.  It often has veins of crandallite.

White Marble:  An opaque stone with a little metallic shimmer to it, similar to Aventurine.
White Onyx:  A semi-translucent White to slightly Yellowish-White stone.  Occasionally with more opaque White banding.
White Quartz:  A translucent White stone, is usually pretty uniform in terms of color, but has varying degrees of opacity.
White Topaz:  Faceted transparent Clear crystals.

Zebra Jasper:  Gray/Green jasper with White zebra lines across the stone.