Alum crystals - that have triangular facets - grown on a silk substrate. The technique used here is called *precipitation from a solution*. Alum crystals are clear and faceted with great definition so they are often compared to diamonds. However these can get so big that it is not really credible that they are diamonds, but they play with light in similar ways.
Alum crystals - that have triangular facets - grown on a silk substrate. The technique used here is called *crystallization*. Alum crystals are clear and faceted with great definition so they are often compared to diamonds. However these can get so big that it is not really credible that they are diamonds, but they play with light in similar ways.
