Welcher Edelstein ist das?
- 128 pages
- 5 hours of reading





Drahokamy a krystaly včetně Krystalové soustavy a stupnice tvrdosti.
Kristallsystem und Härteschlüssel
Photos and information on form, color, origin, and other topics for many specific minerals, gems and crystals. Additional information on mineral formation in the earth.