Which characteristic is expected of a mineral that crystallizes from lava at Earth's surface?

A. large crystals

B. small crystals

C. magnetic crystals

D. hexagonal crystals

Answer: B. small crystals

The volcanic eruption occurs when the pressure is exerted by the hot lava produced in the mantle. It results in the expulsion of gases, rocks and hot liquid in the form of lava on the surface of earth. The lava which comes in the surface of the earth is called as magma. When the magma which crystallizes under surface of the earth that cools at the slow rate and forms a large crystal whereas the magma that crystallizes at the surface, cools at the faster rate and crystallizes into small crystals.

The answer is B. small crystals

Explanation:

Igneous rocks are those that form when magma (molten rock) cools and solidifies. if the cooling occurs quickly on the surface, after a volcanic eruption, rocks with crystals are formed, indistinguishable to the naked eye, known as volcanic or extrusive rocks. Volcanic or extrusive rocks are formed by the solidification of magma (lava) on the surface of the earth's crust, usually after a volcanic eruption. Since the cooling is very fast, mineral ions cannot be organized into large crystals (which means extrusive rocks have small crystal), so volcanic rocks are fine grained.