This may be the mineral crystals in mineral inclusions in Bai Yushi, which are often hard to wear, so it is difficult to remove when grinding. These crystal particles are very small, accounting for only a small part of the whole jade, and generally will not affect the overall look and feel of jade. Therefore, even if these mineral crystals exist in white jade, they are still considered as high-quality jade.

The specific situation needs further appraisal by professional institutions.