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Gemstones


Author: , Ph.D., GIA Graduate Gemologist


Birthstones
birthstones
Birthstones are gems assigned to the month of a person*s birth. They are popular gifts in the U.S.
All About Diamonds
Diamond
Diamond A collection of photos, articles, facts, maps and graphs about diamonds.
Ruby and Sapphire
Ruby and Sapphire
Ruby and Sapphire are the 2nd and 3rd most popular colored stones in the United States.
Tumbled Stones
Tumbled Stones
Tumbled Stones are rocks that have been rounded, smoothed and polished in a rock tumbler.
Gems from Space
Gems from Space
Extraterrestrial Gems A number of materials from space are used as attractive gems.
Opal Photos
Opal
Pictures of Opal A collection of different types of opal from all around the world and Mars too!
Charoite
Charoite
Charoite is a rare purple mineral from Russia used as a gem material and ornamental stone.
Gemstone Book
Gemstones of the World
Gemstones of the World : A book by Robert Schumann. Over one million copies sold.
Emerald
emerald
Emerald is the most popular green gemstone in the United States and most of the world.
American Gemstones
U.S. Gemstones
Mined in America - Small mines in the United States produce a diversity of beautiful gemstones.
Amethyst
Amethyst
Amethyst - the most popular purple gem. It has a beautiful color and reasonable price.
Moonstone
moonstone
Moonstone is one of the world*s most popular gems. A soft glow of light floats under its surface.
Green Gemstones
Green Gemstones
Green Gemstones - emerald, peridot, jade, tsavorite, chrome diopside, chrysoprase, more.
Blue Gemstones
blue gemstones
Blue Gemstones - Most people shopping for a colored stone are looking for something blue.
Geodes
Geodes
Geodes look like ordinary rocks on the outside but can be spectacular inside!
Labradorite
Labradorite
Labradorite is a feldspar gem that can produce bright flashes of iridescent color.
Gem Minerals
Gem Mineral Collections
Gem Mineral Collections are a great way to learn about gem materials. Get yours.
Strontium Titanate
strontium titanate
Strontium Titanate - lab created diamond simulant with fire much stronger than diamond.
Geology of Gems
Geology of Gems
Geology of Gems - The first comprehensive book on the geology of gem deposits.
Goldstone
goldstone
Goldstone is a colorful man-made glass that is full of highly-reflective metallic inclusions.
Turquoise
Turquoise
Turquoise A blue to bluish- green gem material that has been used for over 6000 years.
Garnet
Garnet
Garnet is best known as a red gemstone. It occurs in any color and has many industrial uses.
Blood Diamonds
Blood Diamonds
Blood Diamonds Illegally-traded diamonds that may have been stolen or used to fund conflict.
Ruby and Sapphire
Ruby and Sapphire
Ruby & Sapphire are gem corundums - ruby when red, sapphire when other colors.
Colored Diamonds
colored diamonds
Colored Diamonds are diamonds with a noticeable body color. They can sell for over $1M/carat.
Topaz
Topaz
Topaz is a popular birthstone and the #8 mineral in the Mohs Hardness Scale.
Tourmaline
Tourmaline
Tourmaline - the most colorful mineral and natural gem material on Earth.
Ethiopian Opal
Ethiopian opal
Ethiopian Opal - The new opal heavyweight that might give Australia a run.
Biggest Misconception
Diamonds from Coal
Diamonds Do Not Form From Coal Learn several reasons why the coal origin is false.
Petrified Wood
Petrified Wood
Petrified Wood is a fossilized wood that often serves as a colorful gem material.
Ammolite
Ammolite
Ammolite is a fossil and a gemstone. It is shell material from fossil ammonites.
Gifts That Rock
Gifts That Rock
Gifts That Rock - What are the most popular gift items in the Geology.com store
What Is Jade?
Jade
Jade has been used as a gemstone and a tool-making material for for 1000s of years.
Spodumene
Spodumene
Spodumene is an ore of lithium and the mineral of the gems kunzite and hiddenite.
Tanzanite
tanzanite
Tanzanite was unknown until a few decades ago but it has erupted into wide popularity.
Fire Opal
Fire Opal
Fire Opal is a transparent to translucent opal with a yellow, orange or red background color.
Rock Tumbling
rock tumblers
Rock Tumblers - All about rock tumblers and rock tumbling. Read before you buy a tumbler.
100+ Gems
gem photos
100+ Gems - Photos of over 100 beautiful gems ranging from the popular to the obscure.
Fire Agate
Fire Agate
Fire Agate is a rare brown agate that exhibits iridescent colors of red, orange, yellow and green.
Sunstone
Sunstone
Sunstone A feldspar with aventurescence caused by tiny copper inclusions.
Spinel
Spinel
Spinel The gemstone that was confused with ruby and sapphire for over 1000 years.
Jet
jet
Jet is a black organic gem material that forms from well-preserved woody material.
Organic Gems
Organic Gems
Organic Gems are gems formed from plant or animal materials.
Green Diamonds
Green Diamonds
Green Diamonds - one of the rarest and most valuable diamond colors.
Lapis Lazuli
lapis lazuli
Lapis Lazuli - a metamorphic rock and the most popular blue opaque gemstone in history.
Arkansas Diamonds
Arkansas Diamonds
You Can Be A Diamond Miner! At the Crater of Diamonds mine you can keep what you find.
Gem Beryl
Gem Beryl
Beryl - the mineral of emerald, aquamarine, morganite, heliodor, goshenite, and more.
Magnesite
magnesite
Magnesite is a white mineral that is often dyed to imitate turquoise or dyed outrageous colors for fun.
Star Garnet
Star Garnet
Star Garnets are found in only a few locations worldwide. They are the state gems of Idaho.
Incorrect Names
incorrect gemstone names
Green Amethyst and Yellow Emerald are misleading names according to the FTC.
Diamond Producers
Diamond Producers
Diamonds are mined in many countries and their relative importance changes frequently.
Zoisite
zoisite
Zoisite is a diverse gem. Tanzanite, thulite and anyolite are three of its gem varieties.
Cat's-Eye Opal
Cat's-Eye Opal
Cat's-Eye Opal - a phenomenal opal that exhibits chatoyance when properly cut en cabochon.
Malachite
Malachite
Malachite has served as a gem material, pigment and ore of copper for thousands of years.
Gem Silica
Gem Silica
Gem Silica is a blue chalcedony colored by copper. It is the rarest and most valuable chalcedony.
Chrysoberyl
chrysoberyl
Chrysoberyl an extreme gem. Its hardness is 8.5, can display chatoyance or color-change.
Zircon
Zircon
Zircon is a popular and colorful gem with fire and brightness that rivals diamond.
Tiffany Stone
Tiffany Stone
Tiffany Stone is a rare purple, blue and white rock, mined in Utah, and used as a gem.
Rose Quartz
Rose Quartz
Rose Quartz is the name used for specimens of translucent quartz with a pink color.
Common Opal
Common Opal
Common Opal is a material that does not exhibit the play-of-color seen in precious opal.
Red Beryl
Red Beryl
Red Beryl is one of the rarest gems. Small amounts are mined at one locality in Utah.
Bloodstone
bloodstone
Bloodstone is a dark green jasper with a splatter of red color that looks like blood.
US Diamond Mines
United States Diamond Mines
US Diamond Mines Where are diamonds mined in the United States?
Ant Hill Garnets
Ant Hill Garnets
Ant Hill Garnets - tiny gems that ants haul to the surface and discard on their anthill. Honest!
Benitoite
Benitoite
Benitoite - Geology of the State Gem of California - USGS report from 1911.
Unakite
Unakite
Unakite A gem material composed of green epidote and pink orthoclase.
Peridot
Peridot
Peridot is the gem variety of olivine. Derived from the mantle and rarely from meteorites.
Geology Tools
Geology Tools
Geology Tools - Rock hammers, field bags, hand lenses, maps, hardness picks, gold pans.
Aventurine
Aventurine
Aventurine - a translucent quartz with reflective inclusions that cause aventurescence.
Yellow Diamonds
Yellow Diamonds
Yellow Diamonds are the most valuable yellow gems and the 2nd most common fancy diamond.
Scapolite
Scapolite
Scapolite can be a pretty faceted stone or a translucent cab with cats-eye effects.
Serpentine
Serpentine
Serpentine - a group of metamorphic minerals used as gems and architectural stone.
Chatoyant Gems
cats eye gems
Chatoyant Gems look like the eye of a cat. They have a line of light that moves across the gem.
US Gem Production
US Gemstone Production
U.S. Gemstone Production is very low compared to the U.S. being the largest consumer.
Helenite
Helenite
Helenite is a man-made glass produced by fusing ash from the 1980 Mount St. Helens eruption.
Rhodochrosite
Rhodochrosite
Rhodochrosite : a manganese mineral used as an ore, a pink gem and an ornamental stone.
Peanut Wood?
Peanut Wood
Peanut Wood? Yes! It is a very interesting gem material found in Western Australia.
Ametrine
Ametrine
Ametrine is a bicolor quartz (amethyst + citrine) and a gemstone of growing popularity.
Lepidolite
Lepidolite
Lepidolite - a pink to purple mica sometimes used as a gem. A source of color in pink aventurine.
Facts About Diamonds
Diamond Facts
Facts About Diamonds You are a diamond expert if you know all of these!
Morado Opal
Morado Opal
Morado Opal is a purple variety of common opal which is found in central Mexico.
Brown Diamonds
Brown Diamonds
Brown Diamonds are growing in popularity and are frequently seen in fashion jewelry.
Kyanite
kyanite
Kyanite is a metamorphic mineral used to make porcelain, abrasive products and gems.
Fancy Sapphire
Fancy Sapphires
Fancy Sapphires are gem corundums of any color other than red, blue or colorless.
Smoky Quartz
Smoky quartz
Smoky Quartz - A brown color-variety of the mineral quartz often cut as a gem.
Petrified Palm
Petrified Palm
Petrified Palm is often confused with petrified wood. It is a distinctly different material.
Gemstone Microscopy
gemstone inclusions
Looking Into the Mysteries of Gems and exploring their hidden secrets with a microscope.
Variscite
Variscite
Variscite is a yellowish green to bluish green mineral. It is similar to turquoise and cut as a gem.
Azurite
Azurite
Azurite is a vivid blue copper mineral that can be cut into beautiful cabochon gems.
Iolite
Iolite
Iolite is the gem variety of the mineral cordierite. An alternative to sapphire and tanzanite.
Maw Sit Sit
Maw Sit Sit
Maw Sit Sit is a metamorphic rock and a gem material that was once thought be jade.
Heliodor
Heliodor
Heliodor is a yellow, greenish-yellow or golden yellow beryl used as a gem.
Titanite aka Sphene
Titanite
Titanite is also known as sphene. It is a minor source of titanium and a minor gem.
Cabochons
Cabochons
Cabochons A photo gallery of cabochon gemstones from around the world.
Canadian Diamonds
Canadian Diamonds
Canadian Diamond Mines produce some of the largest and highest quality diamonds!
Chrysoprase
Chrysoprase
Chrysoprase - The translucent green variety of chalcedony that is colored by nickel.
Diopside
Chrome Diopside
Chrome Diopside is a green gemstone that is often used as an alternative stone for emerald.
Turritella Agate
Turritella Agate
Turritella Agate is a brown agate containing snail fossils from the Green River Formation.
Andalusite
Andalusite
Andalusite - exhibits strong pleochroism and often has sets of oriented inclusions.
Prasiolite
Prasiolite
Prasiolite is amethyst that has been heat-treated to a leek-green color.
Moldavite
moldavite
Moldavite is a gem material born about 15 million years ago when a pair of asteroids struck Europe.
Azurmalachite
azurmalachite
Azurmalachite is a mixture of malachite and azurite. It can be a beautiful blue and green gem.
K2 Granite
K2 Granite - aka K2 Jasper
K2 Granite is a white granite with blue orbs of azurite. It is a new gem material from Pakistan.
Apatite
Apatite
Apatite produces gemstones with vivid colors and is popular with collectors.
Gaspeite
gaspeite
Gaspeite is a rare green ore of nickel that has become a popular gem in southwestern jewelry.
Rhodonite
rhodonite
Rhodonite is a pink manganese silicate used as a gemstone, an ornamental stone and an ore.
Iris Agate
Iris Agate
Iris Agate can produce a rainbow of colors when light passes between its thin bands.
Hardness Picks
Hardness Picks
Hardness Picks - Mohs hardness testing with precise and easy-to-use hardness picks.
Sonora Sunrise
Sonora Sunrise
Sonora Sunrise is a gem material of Mexico composed of red cuprite and blue-green chrysocolla.
Polka Dot Agate
Polka Dot Agate
Polka Dot Agate - a translucent blue to white agate with a suspension of colorful dots.
Synthetic Opal
synthetic opal
Synthetic Opal is a man-made material with the play-of-color and appearance of natural opal.