| GADOLINITE (Yttrium Iron Beryllium Silicate) | |
| GAHNITE (Zinc Aluminum Oxide) | |
| * | GALENA (Group) |
| GALENA (Lead Sulfide) | |
| * | GARNET (Group) |
| GASPEITE (Nickel Magnesium Iron Carbonate) | |
| GAYLUSSITE (Hydrated Sodium Calcium Carbonate) | |
| * | GEMSTONES (Class) |
| 0 | GEODES (generally hollow sedimentary rocks) |
| GERSDORFFITE (Nickel Arsenide Sulfide) | |
| 0 | GIBBSITE (Aluminum Hydroxide) |
| GLAUBERITE (Sodium Calcium Sulfate) | |
| GLAUCOPHANE (Sodium Magnesium Iron Aluminum Silicate Hydroxide) | |
| GMELINITE (Hydrated Sodium Calcium Aluminum Silicate) | |
| GOETHITE (Hydrated Iron Oxide) | |
| GOLD (Au) | |
| GOOSECREEKITE (Hydrated Calcium Aluminum Silicate) | |
| GORMANITE (Hydrated Iron Magnesium Aluminum Phosphate Hydroxide) | |
| GOSHENITE (variety of Beryl, Berylium Aluminum Silicate) | |
| 0 | GRAEMITE (Hydrated Copper Tellurate) |
| 0 | GRANITE (an igneous rock with visible crystals) |
| GRAPHITE (Carbon) | |
| GRATONITE (Lead Arsenic Sulfide) | |
| GREENOCKITE (Cadmium Sulfide) | |
| GROSSULAR (Calcium Aluminum Silicate) | |
| GYPSUM (Hydrated Calcium Sulfate) | |
| GYROLITE (Hydrated Calcium Silicate Hydroxide) |