This is a shaped and polished, ready to mount or display, natural Andamooka opal from the mines of Australia.
It is a freeform shape, polished on one side and is 28mm high, 15mm wide, 3mm thick and of 12.20 carats.
These opals are not of the quality from other areas in Australia and are often boiled in sugar to darken the background to enhance the colour plays. This natural opal has a pale brown background, with muted flashes of green, red, blue and yellow.
Not a great stone, which would make an interesting pendant or kept as a large example of this type of opal.