1. Color-changing gemstone

2. Yellow variety of quartz

3. Colorful gemstone

4. Lustrous gemstone formed inside a mollusk

5. Blue-green gemstone

6. Cyclosilicate mineral with various colors

7. Iron oxide mineral used as a gemstone

8. Gemstone with a milky iridescence

9. Common mineral in many gem varieties

10. Blue or violet gemstone

11. Green copper carbonate mineral

12. Green gemstone used symbolically

13. Blue gemstone

14. Reddish-orange variety of chalcedony

15. Fire-resistant gemstone

16. Purple gemstone