| 释义 |
〔chalk〕A soft, compact calcite, CaCO3, with varying amounts of silica, quartz, feldspar, or other mineral impurities, generally gray-white or yellow-white and derived chiefly from fossil seashells. 白垩：一种松软的方解石粉块，CaCO3，含有不等量的硅石、石英、长石或其它矿物杂质，通常为灰白色或黄白色，从贝类化石中制得 |