| Publication Year | 1994 |
| Type | Guide |
| Language | English |
| Length | 160 pages |
| Topic | Gemstones |
| Vintage | Yes |
There is also a section on synthetic gemstones and how they have been created over the centuries, and how the color of stones can be changed by irradiation, heating and staining the stones. Early man made weapons and tools from many varieties of chalcedony including agate, agatized coral, flint, jasper, and petrified wood.