The main considerations for opal pricing are:
1. The TYPE of opal (Black Opal, Semi-Black, White, Crystal, Semi-Crystal)
2. The BRIGHTNESS of the stone (measured from 1 to 5)
3. The BODY TONE (how white or grey the face of the opal is) from (1 to 9).
4. The COLOR(S), Saturation and Value.
5. The PATTERN, consistency, cut, inclusions, and other smaller factors.
I've not even listed all the variables here! So you can see that pricing is tricky. I'm getting better at it, but I still have much to learn.
Contact me if you'd like to know more!