Ice Cubes are of interest to me for two reasons. Firstly, they formed in a similar way to tektites - solidifying/freezing from the outside, towards the centre. See the images below, where the radiating structure is highlighted by trapped bubbles of air. One must remember, however, that when ice freezes it expands, whereas glass contracts.

Secondly, ice cubes suffer from thermal stresses when exposed to dramitically different temperatures . This results in cracking when you put them in your G & T, hopefully I'll get some good images soon.


ABOVE:   Ice cube with radiating structure, as shown by trapped bubbles of air. The ice formed from the outside in. Tektites formed in a similar manner, cooling from the outside in.

ABOVE:   Another ice cube example.

ABOVE:   Another ice cube example.

ABOVE: A broken tektite. This shattered during cleaning and was not dropped at this time. Note the radiating structure.

ABOVE:   Anda Sculpture with a radiating pattern. Anda sculpture is a consequence of chemical etching in the ground. Is the radiaiting pattern related to the internal structure, formed by the tektites cooling history?