Which statement best explains how streak differs from color as a physical property of minerals?

• A. Streak and color are always identical for any given mineral.
• B. Streak refers to the color of a mineral's powder, while color is the appearance of the mineral in bulk.
• C. Streak is only observed in transparent minerals, while color applies to all minerals.
• D. Streak is the mineral's reaction to acid, while color is its appearance.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definition of color in minerals. Color refers to the appearance of the mineral as seen by the naked eye in its bulk form, which can be influenced by impurities, surface tarnish, or weathering.
2. Step 2: Understand the definition of streak. Streak is the color of the mineral in its powdered form, which is obtained by rubbing the mineral on a streak plate (usually unglazed porcelain). This color is often more consistent and characteristic of the mineral itself.
3. Step 3: Recognize that streak is a more reliable physical property for identifying minerals because it is less affected by surface conditions and impurities compared to bulk color.
4. Step 4: Compare the two properties: while color can vary widely for the same mineral due to external factors, streak tends to remain constant and is specific to the mineral's true composition.
5. Step 5: Conclude that the best explanation is that streak refers to the color of a mineral's powder, while color is the appearance of the mineral in bulk.