For the majority of minerals,the streak color obtained when the mineral is scratched against a porcelain plate is ____________.
A) likely to be diagnostic only if the mineral is hard enough to scratch porcelain
B) more variable than the color in hand sample among crystals
C) less variable than the color in hand sample among crystals
D) always dark brown or black

Question

Quizplus · Accepted Answer

Streak color is usually less variable than the color in hand sample among crystals, as it is often determined by the actual color of the mineral's powder. Streak color is obtained when a mineral is scratched against a porcelain plate, which breaks down the mineral's crystal structure and exposes its powder form. This can reveal a consistent color that may differ from any variations in color seen among different crystal faces. Streak color can be useful for identifying minerals because it is not affected by impurities or weathering that may alter the appearance of the mineral's surface.

For the Majority of Minerals,the Streak Color Obtained When the Mineral