The Shapes of Snowflakes is a fascinating categorization of crystal structures from Compound Interest, a chemistry site run by Andy Brunning in the UK. The site has a huge selection of chemistry and science related infographics.
In the Northern Hemisphere at least, the idealised vision of Christmas involves snow. Whilst no one snowflake is exactly the same as another, at least on a molecular level, scientists have none-the-less devised a system of classification for the many types of crystals that snow can form. This graphic shows the shapes and names of some of the groups of this classification.
The number of categories snow crystals can be categorised into has been steadily increasing over the years. In early studies in the 1930s, they were classified into 21 different shape-based categories; in the 1950s, this was expanded into 42 categories, in the 1960s to 80 categories, and most recently in 2013 to a staggering 121 categories.
Science meets Christmas!
You can also download a high-resolution PDF version.