Druze of natural quartz, Rainbow Plated coating. The sample has a slight chip (the result of checking the sample for authenticity).
Nowadays, many fakes of such druses have appeared on the market, namely, quartz crystals are placed on a plaster or clay base, which imitates the growth point and are painted. It is very difficult to determine such a fake by staining - the only thing that gives away such samples is the weight, because it is much lighter than a quartz druse.
This sample corresponds to the photo