What term describes the color of a mineral in powdered form?

The term that describes the color of a mineral in powdered form is "streak." This is determined by rubbing the mineral against a hard, white surface, typically a ceramic plate, to observe the color of the powder left behind. The streak test is important in mineralogy because it provides a more consistent and reliable indication of a mineral's true color than surface color, which can vary based on factors like weathering or impurities in the mineral.

Surface color may refer to the external appearance of the mineral, which can be misleading due to oxidation or other surface changes. Shade and hue are more general terms related to color and do not specifically refer to the powdered form of a mineral. Therefore, "streak" is the precise term used in geology and mineralogy to denote the color observed when a mineral is powdered.