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