druse

noun3

1. •
   A rock surface with a crust of tiny crystals.

   • Occurs as a fine coating over the minerals in druses or cavities in the granite. — 1889
2. •
   An aggregation of calcium oxalate crystals found in certain plants.
3. •
   A tiny yellow or white accumulation of extracellular material that builds up in Bruch's membrane of the eye.