In 1951, the International Commission on Snow and Ice developed the International Classification System and officially named classification types for seven types of snow crystals. Irregular forms, the most common of the seven types, are natural snow crystals that cannot be attributed to one of the other six classifications.
Needles
Needles form at around 23 degrees F, and resemble long and thin column-like needles.
Plates
Plates, which form at 28 degrees, have symmetrical designs and often form elaborate, intricate and radiating patterns.
Columns
Columns, similar to needles, are hollow on both ends; thereby producing a straw-like crystal. A column's hollow end points are not visible to the naked eye.
Capped Columns
Capped columns are a combination of column and plate crystals. Caps are distinguishable due to the existence of plates on both ends, which results in a resemblance to a thread spool.
Stellar Crystals
Stellar crystals, most often associated with holiday imagery, are classified due to their tree-like branching from the center. Fern-like dendrites have leaf-like designs radiating from the tree-like branches.
Spatial Dendrites
This crystal is often referred to as a radiating dendrite. It is easily distinguishable due to radiating arms or plates extending in all three dimensions from the center.
Tags: both ends, from center, seven types, snow crystals