Question

what is streak in mineralogy?
the lines visible within a minerals surface
the pattern created when a mineral breaks
the color of powder produced when a minerals is scraped on unglazed porcelain
the way light reflects off a minerals surface

Explanation:

In mineralogy, streak is defined as the color of the powder produced when a mineral is scraped across an unglazed porcelain plate (a streak - plate). This property helps in mineral identification as the streak color is often more consistent and reliable than the surface color of the mineral.

Answer:

The color of powder produced when a minerals is scraped on unglazed porcelain