Capped column

This is snowflake of unusual and interesting type: capped column. Unlike hollow columns, these crystals have caps on both ends. Caps (they looks like two "normal" snowflakes, which grown parallel to each other at the ends of central column) greatly vary in size, can be simple hexagons or have branches, but usually two caps of same crystal grows almost perfectly identical (thanks to small crystal size), and whole crystal looks very strange, but symmetrical:

Snowflake photo: Capped column

Prints available at Artist website (mirrors at Pixels and FineArtAmerica), RedBubble.com.
Licenses for commercial use - at Shutterstock.com.

These crystals usually bigger than hollow columns, and some specimens, which i've seen, was nearly 2 millimeters long. But still, these snowflake are small, and many people never seen them. In fact, capped columns is not very rare: during many snowfalls you'll see no one, but some snow storms brings huge amount of these snowflakes, separate crystals and in clusters. In this case, they can be seen with naked eye, if you'll catch some snow on dark backdrop (like black woolen mitten) - this will create enough contrast for our eyes.

Caps of this snowflake have hexagonal symmetry, like most other snow crystal types, but, because two caps and column are single crystal, these snowflakes are true 12-sided snow crystals, unlike bigger and "flat" snowflakes with twelve arms (like these: Wheel of time and Twelve months), which formed from two separate snowflakes, collided in the air and continued growth as one crystal (according to Kenneth Libbrecht's Guide to snowflakes).

These snowflakes are difficult target for photographer because of volumetric shape and small size. Unfortunately, i still have no sources for focus stacking, but it's my first relatively good shot of this snowflake type. 8 serial shots aligned and averaged to boost signal-to-noise ratio. Background: dark woolen fabric, natural light (grey cloudy sky), external optics Helios 44M-5, January 2013, Moscow.

Here you'll find new processing of this snowflake, done in 2016, and another capped column - with caps of different size and shape:

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.