efflorescence

n.

  1. Flowering, or state of flowering; the blooming of flowers; blowth.
  2. A redness of the skin; eruption, as in rash, measles, smallpox, scarlatina, etc.
  3. The formation of the whitish powder or crust on the surface of efflorescing bodies, as salts, etc.
  4. The powder or crust thus formed.