Overview of this semiprecious stone's characteristics is followed by a detailed guide to different agate varieties.

Discover the composition of the layered rock, that usually contains much silica. Paragraph also lists other types of silica.

Learn how this Oregon gem mine was discovered, take a tour, and find links to information about agates, fossils, and lapidary work.

Look up the definition that describes the light-colored mineral. Details where the substances may be found.

Find a definition about the fossil residue and its forms and uses. Details where the material can be commonly found.

Provides details on this quartz variety's composition and properties, with links to related topics.

Definition explores the properties of the purplish stone and details where the compound can be found in the world.

Get to know the compositions and properties of the minerals in this group, which includes fluorapatite, chlorapatite, and hydroxyl-apatite.

Find specifications of this mineral, including its specific gravity, physical traits, hardness, and usages.

Find physical characteristics and images of apatite, a calcium phosphate used as a source of phosphorous in fertilizer.

Find details about the precious stone and its color variations. Details the global locations where the stone may be found.

Browse through the basic facts about this common carbonate mineral. Learn about its uses and view specimens.

Provides the composition, class and characteristics of this mineral that is a major ore of arsenic.

Definition discusses this material, which is a composition of multiple minerals. Contains info on its environmental concerns.

Peruse a collection of photographs featuring minerals taken from many different locations around the world. Check out the compound make-ups.

Discover key facts about this crystal's chemical make-up, its physical properties, and its geographic distribution. View photos of samples.

Educational paragraph cites the formula for the blue mineral. Discusses properties that include hardness, specific gravity, and uses.

Learn about the type of rock found in volcanic compositions. With descriptions of how it forms.

Learn about the importance of this rock. Shows photos, describes the formation of the rock, and provides links to basalt research locales.

Outlines the composition, properties, and locations of this mineral, which is perhaps best-known for its green variety, the emerald.

Look up the definition of the beryllium ore. Read about its properties, uses, and chemical formula.

Encyclopedia entry defines this practice of attributing gemstones with one's birthdate as well as providing its estimated origins.

Read about the stone that's also called heliotrope and learn about its blood-stained novelty.

Crumbly rock is profiled in the MSN encyclopedia. Article discusses its volcanic relationships.

Find a wide range of amber jewelry to bid on, from rings to necklaces. Each item page contains a photo, description and owner contacts.

Mineral and gemstone collectors will find amethyst and quartz selections. Also available are jewelry and chimes made from minerals.