Question

galena is a mineral that creates smooth, flat surfaces when it breaks. it is a 2.5 on mohs scale. galena______
choose one option
a has cleavage and is soft
b has fracture and is very hard
c has fracture and a shiny luster
d has cleavage and no streak

Explanation:

• Cleavage is when a mineral breaks along smooth, flat surfaces. Since galena creates smooth, flat surfaces when it breaks, it has cleavage.
• On the Mohs scale, a value of 2.5 indicates that the mineral is soft (as the scale ranges from 1 - 10 with lower numbers being softer).
• Option B is incorrect because it mentions fracture (which is an irregular break, not smooth and flat like cleavage) and being very hard (2.5 is not very hard).
• Option C is incorrect because it mentions fracture (wrong break type) and while galena does have a metallic luster, the key point here is the break type (cleavage) and hardness (soft).
• Option D is incorrect because galena does have a streak (it leaves a gray - black streak).

Answer:

A. has cleavage and is soft