crystally

From crystal +‎ -ly.

crystally (comparative more crystally, superlative most crystally)

1. Like or as a crystal.
   • 1820, Jane Waldie, Sketches descriptive of Italy in the years 1816 and 1817, volume 4, page 320:

     It is clear, yet not crystally transparent; and, though a deep colour, is neither green nor blue […]

   • 25 April, 1861, George Eliot, letter to Charles L. Lewes

     There is a crystally clear river flowing by Vidauban, called the Argent: it rushes along between a fringe of aspens and willows […]

• crystally clear

• crystalline