NGS Rocks and Minerals : Sec. 1: Properties of Minerals

What is a mineral?

• A naturally occurring, inorganic solid with a crystal structure

• A naturally occurring, inorganic liquid with a crystal structure

• A man-made, inorganic solid with a crystal structure

• A naturally occurring, organic solid with a crystal structure

Answer explanation

A mineral is defined as a naturally occurring, inorganic solid with a crystal structure. This excludes liquids, organic materials, and man-made substances, making the first choice the correct answer.

Which of the following is NOT a characteristic of a mineral?

• It must have a definite chemical composition

• It must have a definite shape and volume

• It must be organic

• It must be formed by natural processes

Answer explanation

A mineral must be inorganic, meaning it cannot be organic. The other characteristics, such as having a definite chemical composition, shape, volume, and being formed by natural processes, are essential for a substance to be classified as a mineral.

Tags

NGSS.MS-PS1-1

What determines the color of a mineral?

• The mineral's hardness

• The mineral's density

• The presence of certain elements

• The size of the mineral

Answer explanation

The color of a mineral is primarily determined by the presence of certain elements within its structure. Different elements can absorb and reflect light in various ways, leading to the diverse colors observed in minerals.

What is the Mohs hardness scale used to measure?

• The density of a mineral

• The luster of a mineral

• The hardness of a mineral

• The color of a mineral

Answer explanation

The Mohs hardness scale is specifically designed to measure the hardness of a mineral, indicating its resistance to scratching. Therefore, the correct answer is 'The hardness of a mineral'.

Which mineral is the softest on the Mohs hardness scale?

• Diamond

• Gypsum

• Quartz

• Talc

Answer explanation

Talc is the softest mineral on the Mohs hardness scale, rated at 1. In contrast, diamond is the hardest at 10, while gypsum and quartz are rated at 2 and 7, respectively. Therefore, the correct answer is talc.

What is a crystal system?

• A method to measure mineral density

• A way to classify minerals based on their color

• A grouping of crystal structures based on the number and angle of crystal faces

• A scale to measure mineral hardness

Answer explanation

A crystal system is defined as a grouping of crystal structures based on the number and angle of crystal faces. This classification helps in understanding the symmetry and properties of crystals.

What is cleavage in minerals?

• The way a mineral reflects light

• The color of a mineral's powder

• The ability of a mineral to break along flat surfaces

• The density of a mineral

Answer explanation

Cleavage in minerals refers to the ability of a mineral to break along flat surfaces, which is a key characteristic used to identify and classify minerals.

What is the term for when a mineral breaks apart in an irregular way?

• Fracture

• Cleavage

• Luster

• Streak

Answer explanation

The term 'fracture' refers to the way a mineral breaks apart in an irregular manner, unlike 'cleavage', which describes a smooth, flat break. Therefore, 'fracture' is the correct answer.

Which of the following is a unique property that some minerals may have?

• Ability to change color in sunlight

• Magnetism

• Ability to dissolve in water

• Ability to float on water

Answer explanation

Magnetism is a unique property found in some minerals, such as magnetite, allowing them to attract or repel other magnetic materials. The other options are not unique to specific minerals.

What is luster in terms of mineral properties?

• The way a mineral reflects light

• The hardness of a mineral

• The color of a mineral's powder

• The density of a mineral

Answer explanation

Luster refers to the way a mineral reflects light, which can vary from shiny to dull. This property helps in identifying minerals and is distinct from hardness, color, or density.