| 0 | MACPHERSONITE (Lead Sulfate Carbonate Hydroxide) |
| 0 | MAGNESITE (Magnesium Carbonate) |
| Sale! 2 | MAGNETITE (Iron Oxide) |
| Sale! 5 | MALACHITE (Hydrated Copper Carbonate) |
| 0 | MANGANBABINGTONITE (Calcium Manganese Iron Silicate Hydroxide) |
| 0 | MANGANESE (Mn) |
| Sale! 1 | MANGANITE (Manganese Oxide Hydroxide) |
| * | MARCASITE (Group) |
| Sale! 1 | MARCASITE (Iron Sulfide) |
| 0 | MASSICOT (Lead Oxide) |
| 0 | MELANITE (the black variety of Andradite Garnet) |
| 0 | MELANOPHLOGITE (Silicon Oxide with organic compounds) |
| 0 | MELANTERITE (Hydrated Iron Sulfate) |
| 0 | MENEGHINITE (Lead Antimony Sulfide) |
| 0 | MERCURY (Hg) |
| 0 | MESOLITE (Hydrated Sodium Calcium Aluminum Silicate) |
| 0 | META-ANKOLEITE (Hydrated Potassium Uranyl Phosphate) |
| Sale! 1 | META-AUTUNITE (Hydrated Calcium Uranyl Phosphate) |
| 0 | META-TORBERNITE (Hydrated Copper Uranyl Phosphate) |
| 0 | META-URANOCIRCITE (Hydrated Barium Uranyl Phosphate) |
| Sale! 2 | META-VARISCITE (Hydrated Aluminum Phosphate) |
| 1 | META-ZEUNERITE (Hydrated Copper Uranyl Arsenate) |
| Sale! 1 | MIARGYRITE (Silver Antimony Sulfide) |
| * | MICA (Group) |
| 0 | MICROCLINE (Potasium Aluminum Silicate) |
| 0 | MICROLITE (Calcium Sodium Tantalum Oxide Hydroxide Fluoride) |
| 0 | MILARITE (Hydrated Potassium Calcium Aluminum Beryllium Silicate) |
| 0 | MILKY_QUARTZ (variety of Quartz) |
| Sale! 2 | MILLERITE (Nickel Sulfide) |
| 0 | MIMETITE (Lead Chloroarsenate) |
| 0 | MINASGERAISITE - (Y) (Calcium Yttrium Beryllium Silicate) |
| 0 | MINIUM (Lead Oxide) |
| Sale! 2 | MIXITE (Hydrated Bismuth Copper Arsenate Hydroxide) |
| 0 | MOCTEZUMITE (Lead Uranyl Tellurite) |
| 0 | MOISSANITE (Silicon Carbide) |
| 0 | MOLDAVITE (variety of Tecktite: Meteoric Silica Glass) |
| 0 | |
| 0 | MOLYBDENITE (Molybdenum Sulfide) |
| 0 | MONAZITE (Cerium Lanthanum Thorium Neodymium Yttrium Phosphate) |
| 0 | MONTEBRASITE (Lithium Sodium Aluminum Phosphate Hydroxide Fluoride) |
| 0 | MONTMORILLONITE (Hydrated Sodium Calcium Aluminum Magnesium Silicate Hydroxide) |
| 0 | MORDENITE (Hydrated Calcium Sodium Potassium Aluminum Silicate) |
| 1 | MORGANITE (variety of Beryl, Berylium Aluminum Silicate) |
| 0 | MOSCHELLANDSBERGITE (Silver Mercury or Silver Amalgam) |
| Sale! 2 | MOTTRAMITE (Lead Copper Vanadate Hydroxide) |
| Sale! 1 | MURMANITE (Hydrated Sodium Titanium Niobium Silicate) |
| 0 | MUSCOVITE (Potassium Aluminum Silicate Hydroxide Fluoride) |