Question

what property of rock is being observed when looking for whether or not it scratches other minerals? hardness cleavage luster streak

Explanation:

Hardness is a property that measures a mineral's resistance to scratching. If a rock can scratch other minerals, it indicates its hardness. Cleavage refers to how a mineral breaks along flat planes. Luster is about the way a mineral reflects light. Streak is the color of a mineral in powdered form. So, the property observed when looking at whether a rock scratches other minerals is hardness.

Answer:

hardness