Question

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?
Feldspar is dull, while quartz is glassy.
Feldspar is gray, while quartz is purple.
Feldspar breaks apart when it is rubbed, while quartz does not.
Quartz leaves a white streak when rubbed, while feldspar does not.

Answer 1

Feldspar is dull, while quartz is glassy

Step-by-step explanation:

luster is a sheen or soft glow, especially on reflective surface.