"Negative" Crystals in Ice: A Method for Growth.
Holes bounded by crystal-lographic faces, or "negative" crystals, may be made in ice by inserting a hypodermic needle and connecting it to a vacuum. The evaporation habit changes as a function of temperature and growth rate. This procedure is a simple way of producing mirror-smooth, uncontaminated, crystallographic surfaces in compounds which have high vapor pressure.
Knight
C A
CA
Knight
N C
NC