MINERAL PICTIONARY
DEFINITION MINERALS Are inorganic, naturally occurring substances that have a characteristic chemical composition, distinctive physical properties, and crystalline structure. MINERAL PROPERTIES PROPERTY DEFINITION LUSTER - appearance of a fresh mineral surface in reflected light. PHOTOGRAPH Metallic Luster Non-Metallic Lusters: Vitreous (also known as glassy) Adamantine (also known as brilliant or diamondlike) Resinous (also known as resinlike) Silky Pearly (also known as mother-of-pearl) Greasy (also known as oily) Pitchy (also known as pitchlike) Waxy (also known as waxlike) Dull (also known as earthy) HARDNESS - Resistance of a mineral to abrasion. Measured on Moh s Hardness Scale 1 = softest (talc) to 10 = hardest (diamond) Generally the following can be used: Soft (<5.5) can not scratch glass Hard (>5.5) scratches glass 10-diamond 9-corundum 8-topaz 7-quartz 6-feldspar 5-apatite 4-fluorite 3-calcite 2-gypsum 1-talc CLEAVAGE - tendency of a mineral to break along certain crystallographic planes of weakness, creating flat surfaces. 1 direction of cleavage.
2 directions of cleavage, the angle between the cleavage surfaces can be at 90 degrees or other than 90 degrees. 3 directions of cleavage, the angles between the cleavage surfaces can be at 90 degrees or other than 90 degrees. 4 directions of cleavage. FRACTURE When a mineral breaks forming a surface with no relationship to the internal structure of a mineral (i.e. does not have a cleavage). CONCHOIDAL FRACTURE Type of fracture that exhibits curved surfaces (ex: glass) STREAK - Color of the powdered mineral. Determined by rubbing the mineral on a piece of unglazed porcelain. If mineral has a hardness of 7 + it will scratch the streak plate. Especially useful for minerals with a metallic luster.
SPECIFIC GRAVITY - Heaviness of a mineral. The numeric specific gravity is calculated by the following: S.G. = CRYSTAL FORM weight of mineral weight of equal volume of water HEFT SPECIFC GRAVITY Light < 2.5 Average 2.5 to 4.0 Heavy 4.0 to 5.0 Very heavy > 5.0 The atoms within a crystal are all aligned in a geometrical, repeating three dimensional pattern. Various crystal forms exist Not all minerals exist in a crystal form EFFERVESENCE (i.e. the acid test) Reaction of some minerals (calcite and dolomite) to acid. Bubbles are generated when dilute HCl acid is applied. Some minerals (dolomite) only effervesce when ground to a powder. Video: http://www.youtube.com/watch?v=lw3bwr0ws7m DIAPHANEITY - ability of a mineral to transmit light. OPAQUE No light passes through. TRANSLUCENT Some light passes through. TRANSPARENT Mineral is clear.
DOUBLE REFRACTION Result of the mineral being optically anisotropic. In simpler terms, light passing through the mineral cleavage travels at different speeds depending upon the direction through the crystalline structure. A light ray entering the mineral is split into two separate rays, each traveling a slightly different path to create two separated images. This optical property is also known as birefringence. TENACITY - How tough a mineral is, or how easily a mineral will break, split, crumble or change shape. Brittle If a mineral is hammered and the result is a powder or small crumbs, it is considered brittle. The majority of all minerals are brittle. Sectile Sectile minerals can be separated with a knife, much like wax but usually not as soft. Malleable If a mineral can be flattened by pounding with a hammer, it is malleable. Ductile A mineral that can be stretched into a wire is ductile. Flexible but inelastic Any mineral that can be bent, but remains in the new position after it is bent is flexible but inelastic. Flexible and elastic When flexible and elastic minerals are bent, they spring back to their original position. MAGNETIC The reaction of some minerals to a magnet, or can affect a compass. COLOR Color of the mineral. Note: some minerals come in a variety of colors (top), but some minerals have very distinctive colors (bottom).
FLUORESCENCE The process in which a material absorbs ultraviolet light and then emits light in the visible spectrum. The two pictures shown are the same specimen, the top is in nature light and the bottom is in ultra-violet light. TASTE Distinctive taste of some minerals (ex. Salty, bitter, etc.). ODOR Distinctive odor of some minerals (ex. sulfur: rotten eggs). PHOTOGRAPH Cleavage, 1 Cleavage, 2 Cleavage, 3 Cleavage, 4 Color, many Color, one Crystals Double refraction Effervescence Acid test video Fluorescent, normal Fluorescent, ultraviolet Fracture Fracture, conchoidal Luster, metallic Luster, non-metallic Magnetic Opaque Streak Translucent Transparent CREDIT http://skywalker.cochise.edu/wellerr/mineral/mica/peel.htm http://skywalker.cochise.edu/wellerr/mineral/feldspar/feldspar1.htm http://skywalker.cochise.edu/wellerr/mineral/halite/cleavages5.htm http://skywalker.cochise.edu/wellerr/mineral/fluorite/fluorite1.htm http://skywalker.cochise.edu/wellerr/mineral/fluorite/fluorite1.htm http://skywalker.cochise.edu/wellerr/mineral/sulfur/italy5.htm http://skywalker.cochise.edu/wellerr/mineral/quartz/quartz1.htm http://skywalker.cochise.edu/wellerr/mineral/calcite/calcite1.htm http://www.geol.umd.edu/~jmerck/geol100/lectures/09.html http://www.youtube.com/watch?v=lw3bwr0ws7m http://skywalker.cochise.edu/wellerr/minfluor/pair11.htm http://skywalker.cochise.edu/wellerr/minfluor/pair11.htm http://skywalker.cochise.edu/wellerr/mineral/apatite/massive3.htm http://skywalker.cochise.edu/wellerr/rocks/igrx/obsidian2.htm http://skywalker.cochise.edu/wellerr/mineral/pyrite/pyrite3.htm http://skywalker.cochise.edu/wellerr/mineral/gypsum/gypsum4.htm http://skywalker.cochise.edu/wellerr/mineral/magnetite/magnetite1.htm http://skywalker.cochise.edu/wellerr/mineral/graphite/graphite4.htm http://skywalker.cochise.edu/wellerr/mineral/hematite/hematite1.htm http://skywalker.cochise.edu/wellerr/mineral/fluorite/fluorite10.htm http://skywalker.cochise.edu/wellerr/mineral/gypsum/gypsum1.htm