| 0 | ACANTHITE (Silver Sulfide) |
| 0 | ACTINOLITE (Calcium Magnesium Iron Silicate Hydroxide) |
| 0 | ADAMITE (Zinc Arsenate Hydroxide) |
| 0 | AEGIRINE (Sodium Iron Silicate) |
| 0 | AESCHYNITE (Yttrium Calcium Iron Thorium Titanium Niobium Oxide Hydroxide) |
| 0 | AGATE (variety of Quartz - Silicon Oxide) |
| 0 | AJOITE (Hydrated Potassium Sodium Copper Aluminum Silicate Hydroxide) |
| 0 | ALBITE (Sodium Aluminum Silicate) |
| 0 | ALEXANDRITE (variety of Chrysoberyl- Beryllium Aluminum Oxide) |
| 0 | ALLANITE (Calcium Cerium Lanthanum Yttrium Aluminum Iron Silicate Hydroxide) |
| 0 | ALLUVIAL (a type of unconsolidated sediments) |
| 0 | ALMANDINE (Iron Aluminum Silicate) |
| 0 | ALTAITE (Lead Telluride) |
| 0 | ALUMINUM (Al) |
| 0 | ALUNITE (Potassium Aluminum Sulfate Hydroxide) |
| 0 | AMBER (Succinite: fossilized tree resin) |
| 0 | AMBLYGONITE (Lithium Sodium Aluminum Phosphate Fluoride Hydroxide) |
| 1 | AMETHYST (variety of Quartz- Silicon Oxide) |
| 0 | ANALCIME (Hydrated Sodium Aluminum Silicate) |
| 0 | ANAPAITE (Hydrated Calcium Iron Phosphate) |
| 0 | ANATASE (Titanium Oxide) |
| 2 | ANDALUSITE (Aluminum Silicate) |
| 0 | ANDERSONITE (Hydrated Sodium Calcium Uranyl Carbonate) |
| 0 | ANDESINE (Sodium Calcium Aluminum Silicate) |
| 0 | ANDESITE (an extrusive igneous rock) |
| 0 | ANDRADITE (Calcium Iron Silicate) |
| 0 | ANGELITE (trade name for Anhydrite) |
| 0 | ANGLESITE (Lead Sulfate) |
| 0 | ANHYDRITE (Calcium Sulfate) |
| 0 | ANKERITE (Calcium Iron Carbonate) |
| 0 | ANNABERGITE (Hydrated Nickel Arsenate) |
| 0 | ANORTHITE (Calcium Aluminum Silicate) |
| 0 | ANORTHOSITE (a plutonic igneous rock) |
| 0 | ANTHOPHYLLITE (Magnesium Iron Silicate Hydroxide) |
| 0 | ANTIMONY (Sb) |
| 0 | ANTLERITE (Copper Sulfate Hydroxide) |
| 0 | APATITE (Calcium (Fluoro, Chloro, Hydroxyl) Phosphate) |
| 2 | APOPHYLLITE (Hydrated Potassium Calcium Silicate Hydroxide Flouride) |
| 0 | AQUAMARINE (variety of Beryl, Berylium Aluminum Silicate) |
| 0 | ARAGONITE (Calcium Carbonate) |
| 0 | ARFVEDSONITE (Sodium Iron Magnesium Silicate Hydroxide) |
| 0 | ARGENTITE (Silver Sulfide) |
| 0 | ARGYRODITE (Silver Germanium Sulfide) |
| 1 | ARSENIC (As) |
| 1 | ARSENOPYRITE (Iron Arsenide Sulfide) |
| 0 | ARSENTSUMEBITE (Lead Copper Arsenate Sulfate) |
| 0 | ARTHURITE (Hydrated Copper Iron Arsenate Phosphate Sulfate) |
| 0 | ARTINITE (Hydrated Magnesium Carbonate Hydroxide) |
| 0 | ASTEROIDS (primordial stony or metallic rocks in space) |
| 0 | ASTROPHYLLITE (Potassium Iron Titanium Silicate Hydroxide) |
| 0 | ATACAMITE (Copper Chloride Hydroxide) |
| 0 | AUGELITE (Aluminum Phosphate Hydroxide) |
| 0 | AUGITE (Calcium Sodium Magnesium Aluminum Iron Titanium Silicate) |
| 0 | AURICHALCITE (Zinc Copper Carbonate Hydroxide) |
| 0 | AUSTINITE (Calcium Zinc Arsenate Hydroxide) |
| 0 | AUTUNITE (Hydrated Calcium Uranyl Phosphate) |
| 0 | AXINITE (Calcium Iron Magnesium Manganese Aluminum Boro-Silicate Hydroxide) |
| 1 | AZURITE (Copper Carbonate Hydroxide) |