You are bidding for a  very large piece of natural  Purple and Green Fluorite.

This is a totally natural piece of watermelon fluorite (green and purple), originating from Riemvasmaak, South Africa - so natural, there is still some dirt on it! There is some nice translucency across the top of this piece as well as a lot of large crystals, this is a cabinet sized sample, with a relatively flat base making it ideal for display.

This is a good quality sample weighing 1240g, see the 5p for scale. Some nice colouring on this piece.

Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF₂. It belongs to the halide minerals.