Question

Mineral Properties
Hardness
(scratch test) Color Luster Special
Properties
Feldspar 6
scratches glass pink or white dull/pearly --
Gypsum 2
scratched by fingernail white/gray dull --
Mica 2
scratched by fingernail black/gray shiny splits into thin sheets
Talc 1
easily scratched by fingernail white dull --
Calcite 3
scratched by nail white dull/glassy bubbles with acid

Minerals can be identified by their physical properties such as color, hardness, and luster (type of shine). Mike is holding a rock in his hand. The rock has a mass of about 10 grams. Mike thinks the rock is probably calcite.

Which measurement would best help Mike decide if his rock is calcite?

A.
luster
B.
color
C.
mass
D.
hardness

Answer 1

The best measurement for Mike to take in order to determine if his rock is calcite is:

**D. hardness**

This is because calcite has a hardness of 3 on the Mohs scale, which means it can be scratched by a fingernail but can scratch materials like gypsum. Testing the hardness will help Mike differentiate calcite from other minerals, especially since other options like color and luster can be quite variable and may not be definitive.