Page 73 - Science Course 2 (Book 2)

Mo10-L1a: What are the Materials in Earth’s Geosphere?

Properties such as color, crystal shape, luster, streak, Fracture is the tendency of minerals to break along
hardness, cleavage, and fracture can be used to irregular surfaces.
identify minerals.
A rock is a naturally occurring solid composed of
Luster is the way a mineral’s surface ref ects light. minerals and other materials.

Streak is the color of a mineral’s powder. It is Rocks are classif ed according to how they form.
observed by scratching a mineral across a tile of
unglazed porcelain.

The hardness of a mineral can be ranked on a scale
of 1 to 10 on the Mohs scale, with 1 being the hardest.

1 2 3 4 5 6 7 8 9 10

Softest Hardest
Known Known
Mineral Mineral

1. Talc 2. Gypsum 3. Calcite

Quartz Mica Feldspar
4. Fluorite 5. Apatite 6. Feldspar

Cleavage is the tendency of minerals to break along
smooth, f at surfaces.

7. Quartz 8. Topaz 9.Corundum Cleavage
in 1 direction
Basal

Cleavage
in 2 direction
10. Diamond Prismatic

Cleavage
in 3 direction
Cubic

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