We distinguish between a mineral and a naturally formed glass (such as obsidian)because
A) glass is not produced by geologic processes.
B) glass is organic.
C) glass does not have a fixed crystal structure.
D) glass can be made synthetically as well as occur naturally.

Question

Quizplus · Accepted Answer

One of the key characteristics of minerals is that they have a fixed crystal structure, whereas naturally formed glasses like obsidian do not exhibit this feature. While glass can be made synthetically, this is not the only reason why it is not considered a mineral.

We Distinguish Between a Mineral and a Naturally Formed Glass