What is the difference between the color and streak of a mineral?
The color of a mineral refers to the visible hue of the mineral when it is observed under normal conditions of lighting. It is often the first characteristic noticed when identifying a mineral. The color can vary greatly due to impurities or a combination of elements present in the mineral composition. However, it is important to note that color alone is not a reliable indicator for identifying minerals, as different minerals can have similar colors.
On the other hand, the streak of a mineral refers to the color of its powdered form. It is determined by rubbing the mineral against a hard, white porcelain plate called a streak plate. The streak color often differs from the mineral's external color and provides more consistent results. Streak color is a useful characteristic for discriminating between minerals, as it remains relatively constant for a particular mineral type.