水晶石石英斷片，直徑4到64毫米（0。16到2。51英寸），尤指天然圓形的石英顆粒 A rock fragment between4 and64 millimeters(0.16 and2.51 inches) in diameter, especially one that has been naturally rounded.
光度視網(wǎng)膜亮度單位，相當(dāng)于每平方米有一燭光亮度的表面，通過一平方毫米的瞳孔區(qū)域，到達(dá)視網(wǎng)膜的光線數(shù)量 A unit of retinal illumination, equal to the amount of light that reaches the retina through 1 square millimeter of pupil area from a surface having a brightness of 1 candela per square meter.
這邊緣必須切割到0.02毫米的精密度。 The edge must be machined to 0.02 millimeters.
