Rocks and Minerals includes the scientific studies of mineralogy and petrology. The category also includes web sites devoted to the appreciation, acquisition, and collecting of precious stones, including rockhounding.

Gemstone

Gemstones are generally regarded as: Polished fragments of 'precious' and 'semi-precious' minerals, used for decorative purposes.

Examples of Precious Stones: Diamonds / Sapphires / Rubies / Emeralds

Examples of Semi-Precious Stones: Topaz / Garnet / Spinels.

Examples of Other stones used as gems: Jade / Agate / Opal

Igneous Petrology

Any sites related to Igneous rocks and their study, rather than individual minerals, unless discussed in an entirly igneous setting.

Metamorphic Petrology

Any sites related to Metamorphic rocks and their study, rather than individual minerals unless discussed in an entirly metamorphic setting.

Metamorphic Rocks include: Slate, Gnieiss, Schist, Phyllite, Migmatite, Granulite, Marble, Quartzite.

Meteorites

A Meteorite is a fragment of rock (often with a very high metallic content) that has its origins in outer space.

Minerals

Web sites about minerals and mineralogy.

Non-Metallic Deposits

Examples of non-metallic rocks and minerals of economic interest include coal, gemstones, construction aggregate (gravel or riprap), building stone, salt, gypsum and anhydrite, industrial-grade clays, fluorspar, phosphate, nitrate, and barite. Peat moss is included here because it is a fossil resource (i.e., it is mined faster than it is formed) similar in many respects to coal.

Rock and Mineral Localities

Principally for sites that describe a mineral setting, whether it be from a collectors view point, or the description of a mineral holotype.

Holotype : The locality that describes the mineral - usually where it was first discovered.

Rockhounding

Rockhounding is the pursuit of colorful stones and minerals for making objects of art, including jewelry.

Sedimentary Petrology

Sedimentary rocks are those rocks which form at or near the earth's surface at relatively low temperatures and pressures primarily by either:

1.Deposition by water, wind or ice;

2.precipitation from solution (may be biologically mediated); and /or

3.growth in position by organic processes (e.g., carbonate reefs).

Examples include sandstone, limestone, shale, dolomite, and rock salt.