Gemstones

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Amethyst - the most popular purple gem. It has a beautiful color and reasonable price.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Organic Gems are gems formed from plant or animal materials.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

Sunstone A feldspar with aventurescence caused by tiny copper inclusions.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Spinel The gemstone that was confused with ruby and sapphire for over 1000 years.

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

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

Zoisite is a diverse gem. Tanzanite, thulite and anyolite are three of its gem varieties.

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

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

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

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

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

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

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

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

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

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

Chatoyant Gems look like the eye of a cat. They have a line of light that moves across the gem.

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

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

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

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

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

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

Andalusite - exhibits strong pleochroism and often has sets of oriented inclusions.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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!

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

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

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

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

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

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