Properties of Minerals

Luster Appearance of a fresh mineral surface in reflected light 1. Metallic Luster 2. Vitreous Luster- glassy luster 3. Resinous Luster 4. Pearly Luster 5. Silky luster 1.Pyrite 2.Quartz 3.Orpiment 4.Muscovite 5.Satin Spar Gypsum

Color The wavelength of light that is reflected off of a freshly broken surface of a mineral. Clear Red Orange Yellow Blue Green Indigo Violet Brown Black White

Hardness A mineral’s resistance to abrasion (being scraped) – Mohs scale of hardness

Cleavage The tendency of minerals to break along definite planes of weakness that exist in the internal structure of the mineral Gypsum

Fracture How a mineral breaks Conchoidal- Fracture- surface is smooth and has concentric ridges Fibrous- Breaks into long filaments ObsidianAsbestos

Streak The color of the powder of a mineral after is has been scraped across a hardened ceramic surface

Specific Gravity Ratio of a minerals weight to the weight of an equivalent volume of water. Higher Specific Gravity= Higher Density

Diaphaneity The ability of a thin slice of mineral to transmit light Transparent- allows most light to pass through undistorted Translucent- light passes through but is bent and you cannot resolve images Opaque- no light passes through even the thinnest slice CalciteMuscoviteCinnabar

Crystal Form The assemblage of faces that reflect the internal molecular structure of the mineral

Magnetism Is the mineral attracted to a magnet? Magnetite is the most common mineral that will do this. Hematite

Double Refraction Images appear doubled when viewed through the mineral specimen- Calcite

Taste Most minerals will not have this property. Never taste a sample unless directed to do so. Halite

Odor A characteristic smell from a mineral- Kaolinite smells musty or dank when moistened.

Feel Surface texture of a mineral. Greasy, slick, smooth, rough, soapy, veined Graphite- Greasy

Chemical Reaction HCl acid on Calcite