Minerals and its

Characteristics

Hydroxideis the name for the diatomic anion OH−, consisting of covalently bonded oxygen and hydrogen atoms, usually derived from the dissociation of a base. It is one of the simplest and most pervasive diatomic ions known.

PEROVSKITE

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Square, opaque perovskite on green clinochlore. Very brilliant and with large crystals (2 x 1.5 cm.).

Can be found in Russia. Scale: 6 x 4.5 cm.

Perovskite is named for a Russian mineralogist, Count Lev Aleksevich von Perovski. The mineral was discovered and named by Gustav Rose in 1839 from samples found in the Ural Mountains.

Chemical Formula: CaTiO3 (Calcium Titanium Oxide )

Class: Oxides and Hydroxides Group: PerovskiteUses: A minor ore of titanium and rare

earth metals and as mineral specimens.

Physical CharacteristicsColor is variable from black, brown, gray,

orange to yellow. Luster is submetallic to adamantine,

greasy or waxy.Transparency: Crystals are opaque. Crystal System is Orthorhombic

(pseudocubic). Crystal Habits include commonly

pseudocubic striated crystals. Also found bladed, reniform, granular and massive.

Cleavage is imperfect in one direction.

Fracture is conchoidal. Hardness is 5.5Associated Minerals include chlorite,

talc, serpentine, melilite, andradite, nepheline, sphene and leucite.

Notable Occurrences include the Slatoust district, Ural Mountains, Russia; Sweden; Crestmore Quarries, Riverside County and the Diablo Range, San Benito County, California;

Best Field Indicators are crystal habit, luster, associations, striations and locality.

Crystal System: Orthorhombic

-optical properties-Optical Data: Biaxial (+), a=2.3,

b=2.34, g=2.38, bire=0.0800, 2V(Calc)=88, 2V(Meas)=90. Dispersion r > v.

Pleochroism (x): colorless.

Pleochroism (y): colorless.

Pleochroism (z): colorless.

RL Color: Dark bluish gray.

BRUCITE

A micromount of brown brucite on matrix from the Wood's Chromite Mine, State Line Area, Pennsylvania.

Comments: Crystal cluster of brucite.Location: N'Chwaning Mine, Kalahari Manganese Field, Northern Cape Province, South Africa. Scale: 7 x 5 x 4 cm.

Pearly white, pseudohexagonal crystals of brucite on matrix.Pilcante, Trentino, Italy.Crystal size is 1.6 cm

Chemical Formula: Mg(OH)2, Magnesium

Hydroxide Class: Oxides and Hydroxides

Group: Brucite

Uses: -A minor source of metallic magnesium, a

source of magnesia and as a refractory additive.

- Also used as a flame retardant and also constitutes a significant source of magnesium for industry.

-physical characteristics-Cleavage: {0001} Perfect but may not show in

thin section

Color: Blue, Gray, Gray blue, Yellow, White. = Colorless in thin section

Relief: fair

Birefringence:

Moderate, some of the interference colors are anomalous; a peculiar reddish brown takes the place of the yellow and orange of the first order.

Fracture: Irregular - Flat surfaces (not cleavage) fractured in an irregular pattern. Or uneven

Habit: Fibrous - Crystals made up of fibers.

Habit:

Interference:Massive – Lamellar

Uniaxial (+)

Associated Minerals: calcite, wollastonite, nepheline, talc, aragonite, serpentine, chromite, dolomite, magnesite, periclase and other magnesium minerals.

Notable Occurrences in: Shetland Islands, England; Aesbestos, Wakefield and Black Lake, Quebec, Canada; Aosta, Italy; Brewster, New York, Wood's Mine, Texas, Gabbs, Nevada, Crestmore, California and Berks Co., Pennsylvania, USA.

Best Field Indicators: crystal habit, luster (especially on cleavage surfaces), lack of soapy or greasy feel and flexible but inelastic flakes and fibers.