Here is an opal I just finished cutting - it is a little guy so it is still on its dop so it is easier for me to move it around for the video.  Dops are little pieces of wood or metal that are attached to a stone to make it easier to hold while cutting.  We have had no sun around here lately, so I improvised with a reptile light.  Opals are terrible to try to take pictures and videos of - but this one has a lot of good orange in it that is really not showing up on video.