Thurs-Demo: The one with cleavage

Our department is getting a high-speed video camera. This alone is way-cool. However, while testing out some of the capabilities, it occurred to me that I might be able to use it to demonstrate how some minerals fracture along specific planes of weakness within the crystal. So, to try it out, I took a small calcite crystal and squished it with a pair of pliers.

Mineral Cleavage Test from Matt Kuchta on Vimeo.

It's not perfect - the frame rate (about 3,000 fps) isn't quite fast enough to capture subtle changes just prior to breaking, but it does show off plenty of tiny rhombohedral cleavage fragments spinning off as it breaks. This is one of those demos that is cheap to set up, but filming it requires the use of a rather expensive piece of equipment. But, oh is it pretty...