Bob's Rock Shop: A must visit for all interested in anything rock related.

Bob's Rock Shop: Links List: This is complete. Anything and everything you'd want to know about rocks, minerals, crystals, or gemstones.

Mike Howards' very thorough explaination of the crystalline systems and crystallography.

The Image Gemstones: a storehouse of gemstone pictures and information. Try their parent directory for more images.

 References