Which of the following minerals has greasy luster, no cleavage, and a white streak?
magnetite
pyroxene
talc
mica

streak colors of common minerals

andalusite white or colorless (hardness is about the same as the streak plate).

nephrite colorless (harder than the streak plate).

olivine white or colorless (about the same hardness as the streak plate). often sheds tiny granules instead of a powder.

orthoclase white.

explanation:

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.