| 0 | OBSIDIAN (Volcanic Silica Glass) |
| 0 | OKENITE (Hydrated Calcium Silicate) |
| 0 | OLIGOCLASE (Sodium Calcium Aluminum Silicate) |
| * | OLIVINE (Group) |
| 0 | OLIVINE (Magnesium Iron Silicate) |
| 0 | OLIVENITE (Copper Arsenate Hydroxide) |
| 7 | OPAL (Hydrated Silica) |
| Sale! 3 | ORPIMENT (Arsenic Sulfide) |
| 0 | ORTHOCLASE (Potasium Aluminum Silicate) |
| 0 | OSBORNITE (Titanium Nitride) |
| 0 | OSUMILITE (Hydrated Potassium Sodium Iron Magnesium Aluminum Silicate) |
| 0 | OTAVITE (Cadmium Carbonate) |