Light-Colored Minerals

Minerals with a light color are generally lacking in the elements iron (Fe) and magnesium (Mg). Colors for these minerals are often quite variable - for example quartz comes in white, gray, pink, and purple (amethyst) varieties that differ only in the presence of different trace elements within the basic quartz crystal structure. Any colors other than gray, black, brown (including "gold") and dark green will be considered to be "light". The light-colored minerals listed below are among the most common rock-forming minerals, and are listed in order of decreasing hardness (from hardest at the top to softest at the bottom of the list).

		QUARTZ (SiO2) - Hardness=7 (harder than glass), no cleavage, density 2.7 g/cc, often translucent to transparent, but can occur in a variety of colors (pink=rose quartz, white=milky quartz, gray=smoky quartz, purple=amethyst), has a characteristic glassy luster; very resistant to weathering. Quartz is a silicate mineral.
		FELDSPAR ((K,Na)AlSi3O8) and other compositions - Hardness=6 (harder than glass), two cleavage directions at approximately 90 degree angles, density 2.6-2.8 g/cc, wide variety of colors, but often white to fleshy pink; the most common mineral in igneous rocks. The feldspar minerals are in the silicate group.
		CALCITE (CaCO3) - Hardness=3, three cleavage directions at approximately 75 degree angles, density 2.7 g/cc, commonly colorless to white or light yellow, reacts with dilute HCl; the mineral that most "sea shells" are made of and the primary constituent of the sedimentary rock limestone and the metamorphic rock marble. Calcite is a carbonate mineral.
		HALITE (NaCl) - Hardness=2.5, three cleavage directions at 90 degree angles, density 2.1-2.6 g/cc, generally colorless to light yellow, brown, salty taste; a common evaporite mineral, ordinary table salt. Halite is a halide group mineral.
		MUSCOVITE (KAl3Si3O10(OH)2) - Hardness=2-2.5, one perfect cleavage direction (peels off in thin sheets - one of the mica minerals), density 2.7-3.0 g/cc, colorless to light yellow or light brown; once used for windows. The micas are silicate minerals.
		GYPSUM (CaSO4 . 2H2O) - Hardness=2 (softer than your fingernail), one good and two poor cleavage directions (often difficult to detect), density 2.3 g/cc, generally colorless to white; a common evaporite mineral and the primary component of "sheetrock". Gypsum is a sulfate mineral.

Dark Minerals

Common Minerals

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