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Mineral Identification lab Use your knowledge about rocks to examine and identif

ID: 152615 • Letter: M

Question

Mineral Identification lab Use your knowledge about rocks to examine and identify different rock samples. Record several characteristics of each rock sample including their color, mineral composition and texture Strategies for classifying rocks include, descriptions based on their composition, look and feel Sketch each rock sample used Explain Some of the simple tests that can be used to identify rocks. . Differentiate among some of the common rocks The Rocks that need to be examined are below Halite Obsidian . Quartz Calcite Fluorite

Explanation / Answer

MINERAL IDENTIFICATION

HALITE

Formula: NaCl

Color: Colorless, whitish, yellow, red, purple, or blue

Luster: Vitreous

Hardness: 2½

Streak: White

Tenacity: Brittle

Transparency: Transparent, Translucent

Fracture: Conchoidal

Distinguishing features- Salty taste, softnesss, and crystals formation

OBSIDIAN

Color: black, bluish, mahogany etc the colors due largely to refraction by microscopic bubbles.

Luster: Vitreous

Fracture: Conchoidal

Mohs Hardness: 5 to 5.5

Cleavage: Absent

QUARTZ

Formula: SiO2

Color: Colorless, purple, rose, red, black, yellow, brown, green, blue, orange, etc.

Luster: Vitreous

Hardness: 7

Transparency-Transparent to opaque

Tenacity-Brittle

Distinguishing features-Some specimens fluoresce, especially white and green. Triboluminescent and Piezoelectric. Dissolves in hydrofluoric acid

CALCITE

Formula: CaCO3

Color: White, Yellow, Red, Orange, Blue, Green, Brown, Gray etc.

Luster: Vitreous, Sub-Vitreous, Resinous, Waxy, Pearly

Hardness: 3

Tenacity: Brittle

Fracture: Conchoidal

Streak: white

Distinguishing Properties: At room temperatures it will easily react to dilute acid to effervescence

FLOURITE

Formula: CaF2

Commodity: Fluorite (Fluorspar)

Color: Purple, lilac, golden-yellow, green, colorless, blue, pink, champagne, brown.

Luster: Vitreous, Dull

Hardness: 4

Transparencies: Transparent

Streak: White

Tenacity: Brittle

Cleavage: Perfect

Parting: Indistinct parting

Fracture: Splintery, Sub-Conchoidal

Distinguishing properties- fluoresce, or glow, under ultraviolet light