John investigated the properties of two minerals and recorded his observations: Feldspar is gray, dull, and breaks apart when it is rubbed.
Quartz is purple, glassy, and leaves a white streak when rubbed against a streak plate.

What observations show evidence about the luster of the two minerals? (2 points)
a
Feldspar is dull, while quartz is glassy.

b
Feldspar is gray, while quartz is purple.

c
Feldspar breaks apart when it is rubbed, while quartz does not.

d
Quartz leaves a white streak when rubbed, while feldspar does not.

Question 11 (2 points)