Gemstones

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

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

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

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

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

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

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

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

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

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.

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

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

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.

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

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

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

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

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

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

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

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

Fire Opal is a transparent to translucent opal with a yellow, orange or red background color.

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

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

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

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.

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Organic Gems are gems formed from plant or animal materials.

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

Sunstone A feldspar with aventurescence caused by tiny copper inclusions.

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

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

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

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

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

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

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

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

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

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

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

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

Benitoite - Geology of the State Gem of California - USGS report from 1911.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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