Illustration of assorted gemstones, from Max Bauer's Edelsteinkunde (1909). 1. Lapis lazuli (sanded). 2. Turquoise (sanded). 3. Turquoise (in the rock). 4a. Malachite (natural occurrence). 4b. Malachite (sanded). 5a and 5b. Onyx (from above and from the side). 6. Carnelian (cut and engraved). 7. Agate (carnelian ponyx, as a cut cameo). 8. Chrysoprase (polished). 9. Amber (sanded). (Source: University of Toronto Libraries via Biodiversity Library)