This is large snowflake of stellar dendrite type, 5 or 6 millimeters from tip to tip. It have one reduced branch, but gorgeous pattern in the center:

Crop of snowflake center in full size
7 identical RAW photos, taken as quick series, was aligned and averaged to boost signal-to-noise ratio of this picture. Background: black woolen fabric, diffused light of gray winter sky, external optics Helios 44, March 2013, Moscow, Russia.
Prints available at Artist website (mirrors at Pixels and FineArtAmerica), RedBubble.com.
Licenses for commercial use available at Shutterstock.com.
Here is another snowflake with amazing pattern in the center - Ice crown:
And here you'll find much smaller, star-shaped crystal that i've captured same day - Alcor - with interesting contrast between flower-like inner structure, with curvy lines, and straight lines of outer hexagonal part:
If you want to see more snowflakes, you can browse through all snowflake pictures.
Here you'll find snowflake photo wallpapers in numerous resolutions and screen proportions, up to Ultra HD 4K.
And here is article about snowflake macro photography.