Across
- 5. the preserved remains or traces of past life that are found in rock, soil, or amber
- 7. a fossil that forms when minerals replace the organic material in wood over thousands of years
- 9. consists of distinctly rounded pebbles whose colors contrast sharply with the color of the finer-grained, often sandy, matrix or cement surrounding them
- 10. violet variety of quartz
Down
- 1. a rare, opaque, blue-to-green mineral that's been used as a gemstone for thousands of years
- 2. volcanic glass that forms when magma from a volcano cools and hardens rapidly
- 3. a semi-precious stone that's a type of chalcedony, a fine-grained variety of quartz
- 4. hollow, vaguely spherical rocks
- 6. mineral made of pure carbon, and is the hardest naturally occurring substance on Earth
- 7. fossilized coral that is Michigan's official state stone
- 8. hard, transparent, crystalline mineral made of silicon dioxide