Following a few days of cold weather I found some interested ice crystals outside my front door this morning. Unfortunately we were in a hurry to get to church, but I managed to get the following photographs later in the day. The ruler is 20 cm for comparison.































I think they have formed by vapour deposition from the cold damp air. This is essentially a process of diffusion-limited aggregation, similar to the growth of zinc or silver crystals under electrodeposition, which is the usual chemical fractal demonstration. The delicate fingers would be called "dendrites".



I thought they were pretty cool - such intricate and elegant beauty produced, quite literally, out of the air.