Alphabetical
Gemstone List
Click
on a letter for a list of gems:
A| B| C| D| E| F| G| H| I| J| K| L| M| N| O| P| Q| R| S| T|U| V| W| X|Y |Z
Gemstones that begin
with the letter "O"
Gemstone |
Crystal
System |
Density |
Hardness |
Refractive
index |
Treatments |
Onyx |
micrcrystalline |
2.65 |
7.0 |
1.564-1.660 |
dying, filling |
Opal |
amorphous |
2.15 |
5.0-6.5 |
1.450 |
fracture filling |