Geology 115 Chapter 3

Which of the following statements about hardness is TRUE? A copper penny will scratch gypsum. Apatite is harder than orthoclase. Diamond has a Mohs hardness of 10 because it is 10x harder than talc (hardness of 1). Calcite will scratch fluorite.

A copper penny will scratch gypsum.

What is the difference between a gemstone and a mineral? A gemstone is a mineral, it is simply a mineral prized for use in jewelry or decoration. A mineral is not worth anything and a gemstone is. A gemstone is prettier than a mineral A mineral is not as sparkly as a gemstone

A gemstone is a mineral, it is simply a mineral prized for use in jewelry or decoration.

Why is the color of a mineral not a diagnostic property alone? some minerals come in many colors multiple minerals can the same color the color depends on your vision Both a & b

Both a & b

Please describe, in your own words, the difference between cleavage and fracture:

Cleavage is when a mineral breaks regularly in the same plane or direction, recreating the same shape over and over. Fracture is when a mineral breaks irregularly.

Which of the following statements accurately describes a property that is NOT useful in identifying quartz? Color, because quartz can be in many different colors. Fracture, because quartz does not have fracture. Hardness, because quartz is softer than most mineral on Mohs scale. Crystal habit, because quartz has a fibrous crystal habit.

Color, because quartz can be in many different colors.

Which of the following is a mineral based on the definition? Salt (formula NaCl) amber (tree sap) sugar (formula C6H12O6) glass

Salt is the mineral Halite (NaCl)

Which of the following statements is FALSE? Formation of salt: Formation of table salt is, in mineralogic terms, formation of the halide mineral halite. Formation of table salt takes place when a solution has become saturated. Formation of table salt results in cubic crystals. Formation of table salt is an example of solidification of a melt

Formation of table salt is an example of solidification of a melt.

Which of the of the following statements about gemstones is FALSE? Ruby is a gemstone variety of the common mineral corundum. Many gemstones come from pegmatites, which are particularly coarse-grained igneous rocks. A gemstone is a mineral that has value because of its rarity and beauty. In order to be considered precious or semiprecious, a gemstone must be transparent

In order to be considered precious or semiprecious, a gemstone must be transparent

You are given an unidentified mineral and need to determine its hardness to help identify it. When you press the mineral against the glass plate and try to scratch it no scratches are produced. When you try to scratch it with a copper penny the penny cannot scratch the mineral. What can you say about the unknown mineral's hardness? It is somewhere between 3.5 and 5.5 It is 6 or more It is softer than the penny It is harder than glass

It is somewhere between 3.5 and 5.5

Fluorite is a 4 on the hardness scale, Topaz is an 8. Is Topaz Twice as hard as Fluorite?

No

Which of the following is Not a mineral? An oyster shell, because it's not crystalline A gold nugget, because it's a native metal Pyrite, because it's a chemical compound Oil, because it's a liquid, not a solid

Oil, because it's a liquid, not a solid

Which is NOT a physical property of commonly used in the lab or field to identify minerals? X-ray diffraction color specific gravity luster

X-ray diffraction

Calcite and aragonite mineral that constitute clam shells are examples of which method of mineral formation? biomineralization solidification of melt precipitation from a solution solid-state diffusion

biomineralization Calcite and aragonite minerals that constitute clam shells are examples of biomineralization - a method of mineral formation.

The tendency of a mineral to break and produce smooth, curving, shell-shaped surfaces is termed: conchoidal fracture luster cleavage streak

conchoidal fracture

There are two physical properties of minerals that both result in smooth, flat surfaces with specific angles between them. The first property is externally visible and is the result of how the mineral forms; the second is inherently internal and is the result of breaking a sample of the mineral. These properties are called crystal habit and cleavage hardness and cleavage cleavage and hardness cleavage and crystal habit

crystal habit and cleavage

Diamonds and graphite are examples of: polymorphs crystal structures sulfate minerals cleavage

polymorphs

Which of the following groups of silicate minerals exhibits a single cleavage in one direction? sheet silicates framework silicates independent tetrahedra silicates single-chain silicates

sheet silicates

When you scrape a mineral along a ceramic plate to observe the color of its powder, you are checking the physical property known as streak luster cleavage specific gravity

streak

Graphite is: the "lead" in the pencil you write with the polymorph of galena harder than glass pure silicon

the "lead" in the pencil you write with