Properties of Minerals

Properties of MineralsLusterAppearance of a fresh mineral surface in reflected light

1. Metallic Luster

2. Vitreous Luster- glassy luster

3. Resinous Luster

4. Pearly Luster

5. Silky lusterPyriteQuartzOrpimentMuscoviteSatin Spar GypsumColorThe wavelength of light that is reflected off of a freshly broken surface of a mineral.

ClearRedOrangeYellowBlueGreenIndigoVioletBrownBlackWhite

HardnessA minerals resistance to abrasion (being scraped)Mohs scale of hardness

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

GypsumFractureHow a mineral breaks

Conchoidal- Fracture- surface is smooth and has concentric ridgesFibrous-Breaks into long filaments

Obsidian Asbestos StreakThe color of the powder of a mineral after is has been scraped across a hardened ceramic surface

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

DiaphaneityThe ability of a thin slice of mineral to transmit lightTransparent- 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

Calcite MuscoviteCinnabar Crystal FormThe assemblage of faces that reflect the internal molecular structure of the mineral

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

Hematite Double RefractionImages appear doubled when viewed through the mineral specimen- Calcite

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

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

FeelSurface texture of a mineral. Greasy, slick, smooth, rough, soapy, veined

Graphite- GreasyChemical Reaction

HCl acid on Calcite