A small ice crystal of the hexagonal tabular form; the distance across the crystal from one side of the hexagon to the opposite side may be as large as about 1 millimeter, and the thickness perpendicular to this dimension is of the order of one-tenth as great; this crystal form is usually formed at temperatures of ?10 to ?20øC by sublimation; at higher temperatures the apices of the hexagon grow out and develop dendritic forms.
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