Gemstones

Birthstones are gems assigned to the month of a person*s birth. They are popular gifts in the U.S.

Diamond A collection of photos, articles, facts, maps and graphs about diamonds.

Strawberry Quartz is a red to pink quartz with inclusions that look like strawberry seeds.

Blue Gemstones - Most people shopping for a colored stone are looking for something blue.

Tumbled Stones are rocks that have been rounded, smoothed and polished in a rock tumbler.

Green Gemstones - emerald, peridot, jade, tsavorite, chrome diopside, chrysoprase, more.

Ethiopian Opal - The new opal heavyweight that might give Australia a run.

100+ Gems - Photos of over 100 beautiful gems ranging from the popular to the obscure.

Ruby and Sapphire are the 2nd and 3rd most popular colored stones in the United States.

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.

Moonstone is one of the world*s most popular gems. A soft glow of light floats under its surface.

Pictures of Opal A collection of different types of opal from all around the world and Mars too!

Geodes look like ordinary rocks on the outside but can be spectacular inside!

Blood Diamonds Illegally-traded diamonds that may have been stolen or used to fund conflict.

Geology of Gems - The first comprehensive book on the geology of gem deposits.

Mined in America - Small mines in the United States produce a diversity of beautiful gemstones.

Gem Mineral Collections are a great way to learn about gem materials. Get yours.

Gemstones of the World : A book by Robert Schumann. Over one million copies sold.

Emerald is the most popular green gemstone in the United States and most of the world.

Andalusite is a metamorphic mineral and a strongly pleochroic gem material.

10 Gemmy Facts About Spinel - Is spinel the world*s most overlooked gem?

Turquoise A blue to bluish- green gem material that has been used for over 6000 years.

Strontium Titanate - lab created diamond simulant with fire much stronger than diamond.

Fancy Sapphires are gem corundums of any color other than red, blue or colorless.

Ammolite is a fossil and a gemstone. It is shell material from fossil ammonites.

Labradorite is a feldspar gem that can produce bright flashes of iridescent color.

Cat*s Eye Gems look like the eye of a cat. They have a line of light that moves across the gem.

Goldstone is a colorful man-made glass that is full of highly-reflective metallic inclusions.

Extraterrestrial Gems A number of materials from space are used as attractive gems.

Fire Agate is a rare brown agate that exhibits iridescent colors of red, orange, yellow and green.

Spodumene is an ore of lithium and the mineral of the gems kunzite and hiddenite.

Organic Gems are gems formed from plant or animal materials.

You Can Be A Diamond Miner! At the Crater of Diamonds mine you can keep what you find.

Citrine is the transparent variety of quartz with a yellow to orange to reddish color.

Topaz is a popular birthstone and the #8 mineral in the Mohs Hardness Scale.

Rock Tumblers - All about rock tumblers and rock tumbling. Read before you buy a tumbler.

Ant Hill Garnets - tiny gems that ants haul to the surface and discard on their anthill. Honest!

Tourmaline - the most colorful mineral and natural gem material on Earth.

Diamonds Do Not Form From Coal Learn several reasons why the coal origin is false.

Garnet is best known as a red gemstone. It occurs in any color and has many industrial uses.

Red Beryl is one of the rarest gems. Small amounts are mined at one locality in Utah.

Hardness Picks - Mohs hardness testing with precise and easy-to-use hardness picks.

Opalite is a word that can refer to either common opal or a man-made opalescent material.

Petrified Wood is a fossilized wood that often serves as a colorful gem material.

Star Garnets are found in only a few locations worldwide. They are the state gems of Idaho.

Malachite has served as a gem material, pigment and ore of copper for thousands of years.

Sunstone A feldspar with aventurescence caused by tiny copper inclusions.

Bloodstone is a dark green jasper with a splatter of red color that looks like blood.

U.S. Gemstone Production is very low compared to the U.S. being the largest consumer.

Aquamarine is a popular blue gemstone that serves as a birthstone for the month of March.

Peridot is the gem variety of olivine. Derived from the mantle and rarely from meteorites.

Morganite is an orange to pink gemstone, a variety of beryl, that is growing rapidly in popularity.

Diamonds are mined in many countries and their relative importance changes frequently.

Tiffany Stone is a rare purple, blue and white rock, mined in Utah, and used as a gem.

Ruby & Sapphire are gem corundums - ruby when red, sapphire when other colors.

Green Diamonds - one of the rarest and most valuable diamond colors.

US Diamond Mines Where are diamonds mined in the United States?

Cat's-Eye Opal - a phenomenal opal that exhibits chatoyance when properly cut en cabochon.

Unakite A gem material composed of green epidote and pink orthoclase.

Beryl - the mineral of emerald, aquamarine, morganite, heliodor, goshenite, and more.

Zircon is a popular and colorful gem with fire and brightness that rivals diamond.

Rhodochrosite : a manganese mineral used as an ore, a pink gem and an ornamental stone.

Lab-Grown Diamonds What are they? Can people really make diamonds? Are they real?

Rose Quartz is the name used for specimens of translucent quartz with a pink color.

Common Opal is a material that does not exhibit the play-of-color seen in precious opal.

Tanzanite was unknown until a few decades ago but it has erupted into wide popularity.

Azurmalachite is a mixture of malachite and azurite. It can be a beautiful blue and green gem.

Jet is a black organic gem material that forms from well-preserved woody material.

Ametrine is a bicolor quartz (amethyst + citrine) and a gemstone of growing popularity.

Facts About Diamonds You are a diamond expert if you know all of these!

Cabochons A photo gallery of cabochon gemstones from around the world.

Scapolite can be a pretty faceted stone or a translucent cab with cats-eye effects.

Jade has been used as a gemstone and a tool-making material for for 1000s of years.

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.

Morado Opal is a purple variety of common opal which is found in central Mexico.

Sugilite is a rare mineral and a gemstone best known for its vibrant pink to purple color.

Gifts That Rock - What are the most popular gift items in the Geology.com store?

Moldavite is a gem material born about 15 million years ago when a pair of asteroids struck Europe.

Looking Into the Mysteries of Gems and exploring their hidden secrets with a microscope.

Lepidolite - a pink to purple mica sometimes used as a gem. A source of color in pink aventurine.

Green Amethyst and Yellow Emerald are misleading names according to the FTC.

Opalized Wood is a gem material consisting of wood that has been replaced by opaline silica.

Goshenite is the colorless variety of the mineral beryl and a gem of interest mainly to collectors.

Blue Topaz - The most popular topaz for jewelry. The color is usually a product of treatment.

Chrysoprase - The translucent green variety of chalcedony that is colored by nickel.

Lapis Lazuli - a metamorphic rock and the most popular blue opaque gemstone in history.

Iolite is the gem variety of the mineral cordierite. An alternative to sapphire and tanzanite.

Smoky Quartz - A brown color-variety of the mineral quartz often cut as a gem.

Serpentine - a group of metamorphic minerals used as gems and architectural stone.

Kyanite is a metamorphic mineral used to make porcelain, abrasive products and gems.

Peanut Wood? Yes! It is a very interesting gem material found in Western Australia.

Sonora Sunrise is a gem material of Mexico composed of red cuprite and blue-green chrysocolla.

K2 Granite is a white granite with blue orbs of azurite. It is a new gem material from Pakistan.

Imitation Opal is man-made and looks like opal, but without the same composition or structure.

Charoite is a rare purple mineral from Russia used as a gem material and ornamental stone.

Rhodonite is a pink manganese silicate used as a gemstone, an ornamental stone and an ore.

Titanite is also known as sphene. It is a minor source of titanium and a minor gem.

Gaspeite is a rare green ore of nickel that has become a popular gem in southwestern jewelry.

Apatite produces gemstones with vivid colors and is popular with collectors.

Geology Tools - Rock hammers, field bags, hand lenses, maps, hardness picks, gold pans.

Smithsonite is a zinc carbonate mineral, an ore of zinc, and a minor gemstone.

Yellow Diamonds are the most valuable yellow gems and the 2nd most common fancy diamond.

Colored Diamonds are diamonds with a noticeable body color. They can sell for over $1M/carat.

Magnesite is a white mineral that is often dyed to imitate turquoise or dyed outrageous colors for fun.

Hemimorphite is an ore of zinc that can often be cut into gems with spectacular blue color.

Iris Agate can produce a rainbow of colors when light passes between its thin bands.

Turritella Agate is a brown agate containing snail fossils from the Green River Formation.

Chrysoberyl an extreme gem. Its hardness is 8.5, can display chatoyance or color-change.

Petrified Palm is often confused with petrified wood. It is a distinctly different material.

Helenite is a man-made glass produced by fusing ash from the 1980 Mount St. Helens eruption.

Synthetic Opal is a man-made material with the play-of-color and appearance of natural opal.

Heliodor is a yellow, greenish-yellow or golden yellow beryl used as a gem.

Prasiolite is amethyst that has been heat-treated to a leek-green color.

Variscite is a yellowish green to bluish green mineral. It is similar to turquoise and cut as a gem.

Azurite is a vivid blue copper mineral that can be cut into beautiful cabochon gems.

Canadian Diamond Mines produce some of the largest and highest quality diamonds!

Chrome Diopside is a green gemstone that is often used as an alternative stone for emerald.

Aventurine - a translucent quartz with reflective inclusions that cause aventurescence.

Brown Diamonds are growing in popularity and are frequently seen in fashion jewelry.

Maw Sit Sit is a metamorphic rock and a gem material that was once thought be jade.

Polka Dot Agate - a translucent blue to white agate with a suspension of colorful dots.

Gem Silica is a blue chalcedony colored by copper. It is the rarest and most valuable chalcedony.

Dig for Gems at dozens of sites across the United States. Keep what you find at most locations.