|Finland Snowflakes imaged on New Year's Day by Marko Riikonen (Optics site, Marko's Snowflakes). İMarko Riikonen, shown with permission.
These snowflakes shout out their six-fold symmetry. Although the hexagons are not always regular (as in the flake at right) the angles between their sides are always 60, 120 or 90 degrees.
Snowflakes are larger and more ornamented versions of the plate and column crystals that form halos. Dendritic growth by condensation from water vapour occurs along the three 'a' axes of the crystal to form the star-like appendages.
Sometimes the 'star' is doubled on the upper and lower faces of short columns.
More of Marko's snowflakes here.