Question

What is the color of a powdered mineral formed when rubbing it against an unglazed porcelain tile? A) luster B) density C) hardness D) streak

Short answer

The color of a powdered mineral formed on the tile is called the streak.

Step-by-step solution

Identify the Problem

The exercise is asking for the property of a mineral that describes the color of its powder when rubbed against an unglazed porcelain tile.

Understand Key Terms

Understand that the key term here is 'color of a powdered mineral'. The process of rubbing a mineral on an unglazed porcelain is known as a 'streak test'.

Review Answer Choices

Evaluate the answer choices: - A) Luster refers to how light reflects from the mineral's surface, not its powdered color. - B) Density measures the mass per unit volume of a mineral, unrelated to the color of its streak. - C) Hardness refers to the ability of a mineral to resist scratching. - D) Streak is the correct term for the color of the powdered form of the mineral.

Select the Correct Answer

Based on the understanding from previous steps, the correct answer is D) streak, as it directly relates to the color of a powdered mineral from the streak test.

Key concepts

Mineral Properties

Minerals are naturally occurring inorganic substances with a specific chemical composition and structure. Each mineral has a distinct set of physical properties that can help with identification. Some common mineral properties include:

• Color: While the outer appearance provides some hints, it's not a reliable property since impurities can alter the visible color.
• Luster: Indicates how a mineral reflects light. Descriptors include metallic, glassy, and dull.
• Hardness: Measured using the Mohs scale, this property determines a mineral's resistance to scratching. Talc is the softest, while diamond is the hardest.
• Density: Also known as specific gravity, it reflects the mineral's mass per unit volume.
Streak: This is the color of the mineral in its powdered form, revealed when scraped on a streak plate.

Understanding these properties is crucial for determining a mineral's identity. Each property provides a clue, and together they form a comprehensive profile used by geologists.

Mineral Identification

When identifying minerals, it is essential to use a systematic approach. By evaluating various properties, one can distinguish one mineral from another.

• Streak Test: Despite a mineral's external color, its powdered streak color remains consistent. This makes it a helpful tool for identification.
• Hardness Test: This is performed using items of known hardness, such as a steel nail or a piece of glass. If a mineral can scratch the glass, it is harder than glass.
• Luster Observation: Observe the mineral under a light source to determine how it reflects light.
• Other Tests: Include checking for magnetism, reaction to acids, and presence of cleavage or fracture.

Using these various tests ensures a reliable and accurate identification. It's like being a mineral detective, gathering clues until the identity is uncovered.

Geological Tests

Geologists use geological tests to study minerals and better understand the Earth's composition. These tests help in both identification and evaluating a mineral's properties.

• Streak Test: Involves rubbing a mineral across an unglazed porcelain tile. The color left helps in identifying the mineral.
• Hardness Test: Utilizes the Mohs scale to compare the hardness of the mineral with known substances.
• Density Measurement: By calculating density, geologists can deduce the type of mineral, providing insights into its formation conditions.
• Physical and Chemical Testing: These tests, sometimes performed in labs, can reveal detailed insights into mineral structure and composition.

Conducting these tests requires care and precision. They contribute to broader geoscientific studies, offering crucial data on Earth's processes.