While researching about the history of snowflake exploration, I really sifted through the Internet and bookstores to extract any tiny bit of information I could possibly find about scientists and explorers who talked about ice and snow crystals.
It is pretty fascinating, once you realize the degree of efforts these men went through to gather this wonderful data.
One of the more fascinating finds is the Haeckel's Art Forms from Nature publication. He didn't study snowflakes, but he did illustrate minute ocean life which he hand-illustrated and catalogued while he observed the life forms through the eye of a new invention, the microscope.
The resulting images are absolutely jaw-droppingly awesome. I included a small sample of Haeckel's images so that children can be introduced to such wonder.
Read Kenneth Libbrecht's "Snowflakes" for more information.
View a screen shot of the Woodcut by Olaus Magnus taken from an article by F. Eijgenraam NRC Handelsblad (14 Feb. 1991) (on page 8 of a very large pdf file)
Earliest documented mentions of snow shape and formation:
"Flowers of plants and trees are in general five-pointed. However, flowers of snow, which are called ying, are always six-pointed."
"The reason why snowflakes are six-pointed is because they are only half-frozen rain (xian) (i.e. water) split open by violent winds, and so they must be six-pointed. If one throws a lump of mud on the ground it will splash into a radiating, angular petal-like form. Now 6 is a yin number; and gypsum also is six-pointed with sharp prismatic angular edges. Everything is due to the number inherent in nature. "
"Snow is the ultimate (state) of yin and completely possesses the number of Water (i.e. 6). Every snow-flake is six-pointed. Frost and snow are due to the condensation of rain and dew. Water is is generatd by Metal. A surplus of qi reveals the Mother (i.e. Metal). Hence frost and snow are all white."
Earliest Mentions Source: Li, Qi and Shu: An Introduction to Science and Civilization in China (Dover Science Books).