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Opalized Wood is a gem material consisting of wood that has been replaced by opaline silica.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