石英在摩氏硬度计中属于哪一级别_______

A、<span style="font-family: 宋体;">5&nbsp;</span>

B、<span style="font-family: 宋体;">6&nbsp;</span>

C、<span style="font-family: 宋体;">7&nbsp;</span>

D、<span style="font-family: 宋体;">8</span>