Question

Which term refers to the resistance of a mineral to scratching? A. hardness C. luster B. specific gravity D. fracture

Short answer

The term is hardness.

Step-by-step solution

Identifying the Problem

The exercise asks us to identify which term refers to a mineral's resistance to scratching from the given options.

Understanding Each Term

We have four terms to consider: hardness, luster, specific gravity, and fracture. We need to know what each term means. - Hardness: This measures a mineral's resistance to being scratched. - Luster: This describes how light reflects off the surface of a mineral. - Specific gravity: This is the ratio of the mineral's density compared to the density of water. - Fracture: This describes how a mineral breaks along irregular surfaces.

Matching the Definition

The definition given is resistance to scratching. Based on the understanding of the terms: - Hardness is directly associated with scratching. - Luster, specific gravity, and fracture do not relate to scratching resistance.

Selecting the Correct Term

Since 'hardness' is the term that defines a mineral's resistance to being scratched, it matches the required definition perfectly.

Key concepts

Mineral Identification

Minerals are the building blocks of rocks and play a critical role in geology. Mineral identification is an essential skill in this field. When identifying minerals, geologists analyze various characteristics to determine their type. Each mineral has a unique set of properties, making them identifiable.
To successfully identify a mineral, the following considerations are critical:

• Color: Often one of the first observations, but not always reliable due to variations in impurities.
• Streak: The color of the mineral in powder form, often more consistent than the visible color.
• Hardness: This is measured by resisting scratches. Mohs Scale is often used for this purpose.
• Cleavage and Fracture: The way a mineral breaks can reveal its internal structure. Cleavage refers to smooth breaks, while fracture is irregular.
• Luster: How the mineral reflects light, ranging from metallic to dull.

Each characteristic helps in compiling a profile to correctly match the mineral with the correct type.

Physical Properties of Minerals

The physical properties of minerals are key to their identification and classification. These properties are determined by the mineral's composition and internal atomic structure. Here are some crucial physical attributes:

• Hardness: This indicates a mineral's resistance to being scratched. It's a critical factor in mineral identification.
• Density and Specific Gravity: Density refers to mass relative to volume, while specific gravity is a dimensionless quantity comparing density to water. It provides clues about the mineral's composition.
• Luster: Differentiates between metallic and non-metallic minerals, based on how their surface interacts with light.
• Cleavage and Fracture: Describes the way a mineral breaks under pressure. Cleavage creates smooth planes, fractures are rough and uneven.
• Color and Streak: The visible color might vary, but streak shows the true color of its powdered form, offering reliable identification.

Understanding these properties can provide invaluable insight into the mineral's identity and practical applications in real-world scenarios.

Mohs Scale of Hardness

The Mohs scale of hardness is a tool for miners and geologists alike, providing an easy method for testing mineral hardness. Developed by Friedrich Mohs in 1812, this scale ranks minerals based on their ability to resist scratches. It helps determine which minerals are harder or softer compared to others.

• The scale ranges from 1 to 10, with 1 being the softest and 10 the hardest.
• Talc is rated as 1, indicating that it's very easy to scratch.
• Diamond, topping the scale at 10, is the hardest known natural mineral.
• This system utilizes common objects; fingernails (hardness of 2.5) and glass (hardness around 5.5) are used to test mineral surfaces.
• While it's not an exact measurement of hardness, it provides a comparative tool to categorize minerals.

By using the Mohs scale, geologists can effectively confirm the hardness of a mineral and play an important part in identifying it.