Mineralogy 3rd set

serpentine

Appearance: Opaque to translucent, light, soft, infusible, and susceptible to acids Lustre: Vitreous, silky, or greasy Structure: Microcrystalline and massive, never found as single crystals Color: Usually green, yellow, and black Inclusions: Magnetite, chromite, or other minerals Fracture: Flexible (antigorite) or uneven (chrysolite) Texture: Mesh-like, visible with polarized light. fibrous . 2.5-4

olivine

Chemical Composition(Fe,Mg)2SiO4), Iron - Magnesium SilicateColorPale olive green to yellow-green, occasionally brown.CleavagePoor cleavage in two directions at 90 degrees.Hardness6.5 to 7 (very hard)Specific Gravity3.2 (Mg-rich variety) to 4.3 (Iron-rich variety) (average weight)

Plagioclase

Chemical CompositionRanges from NaAlSi3O8 (Albite) to CaAl2Si2O8 (Anorthite)Hardness6 to 6.5 (harder than glass)Specific GravityIncreases from 2.6 to 2.8 depending on amount of calcium.LusterIncreases from 2.6 to 2.8 depending on amount of calcium.StreakWhite

Labradorite

Chemical Formula:(Ca,Na)(Si,Al)4O8Diaphaneity:Translucent to transparentFracture:Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.Habit:Crystalline - Coarse - Occurs as well-formed coarse sized crystals.

Hornblende

Color: Black, dark green, brown, or opaque green Luster: Vitreous, submetallic, or dull Transparency: Generally opaque, but thin crystals or exceptional specimens can be translucent Hardness: 5-6 on the Mohs scale of mineral hardness Specific gravity: 3.0 to 3.6 Crystal system: Monoclinic; 2/m Cleavage: Imperfect in two directions at 56 and 124 degrees Fracture: Uneven

Andalusite

Color: Greenish brown, yellowish green, pinkish brown, orangy brown, white, gray Hardness: 6.5 to 7.5 on the Mohs scale Density: 3.1 to 3.2 Fracture pattern: Uneven or partially conchoidal Cleavage: Good to poor Luster: Vitreous

Jasper

Color: Usually red, yellow, brown or green in color; and rarely blue. Luster: Dull vitreous to greasy . Transparency: Translucent to opaque. Crystal System: Hexagonal-R; 32 (trigonal-trapezohedral) Crystal Habits: Massive microgranular quartz.

Enstatite

Color: White, yellowish green, brown, greenish white, or gray Density: 3.1-3.3, average = 3.2 Diaphaneity: Translucent to opaque Fracture: Brittle Hardness: 5.5-6.5 on the Mohs scale Cleavage: Perfect in two directions at 90 degrees Luster: Vitreous

Zircon

ColorColorless, yellow, brown, orange, red, violet, blue and greenHardness6-1/2 to 7-1/2 (Mohs)Specific Gravity3.93 - 4.74

Amazonite

ColorPastel blue-green, Deep green/blue (Russian)Hardness6 (Mohs)Specific Gravity2.5 - 2.6Refractive Index1.522 - 1.530

Muscovite

ColorUsually colorless, white or silver, occasionally yellow or brown.CleavageSingle perfect cleavage to produce thin sheets or flakes.Hardness2 to 2.5 (very soft)

Silimanite

HabitAcicular Long, slender prisms Fibrous Subparallel aggregates and splays Fine-grained fibrous matsColorWhite to brownHardness6 to 7Specific gravity3.23

Potassium Feldspar

Hardness6 > GlassCleavageYes Prismatic at right anglesStreakNoneColorPink or White

Wollastonite

Hardness: 4.5-5 on the Mohs scale Density: 2.86-3.09 Streak: White Color: White, gray-white, light green, pinkish, brown, red, yellow Lustre: Vitreous, pearly

chert

Hardness: Chert has a hardness of seven on the Mohs scale. It's as hard as crystalline quartz. Fracture: Chert breaks with a conchoidal (shell-shaped) fracture. This creates very sharp edges that don't dull easily. Texture: Chert has a smooth, non-clastic sedimentary texture. Luster: Chert has a waxy luster.

Prehnite

Hardness:6-6.5 - Orthoclase-PyriteLuminescence:Fluorescent, Short UV=blue white mild peach, Long UV=yellow.Luster:Vitreous - Pearly

augite

Mohs scale hardness 5.5 to 6 LusterVitreous, resinous to dullStreakGreenish-whiteDiaphaneity

biotite

highly perfect basal cleavage, and consists of flexible sheets, or lamellae, which easily flake off.

Chlorite

typically green in color, have a foliated appearance, perfect cleavage, and an oily or soapy feel.