Opal valuation

[m-gems112]

I have a 3.45ct Mintabie opal which I am struggling to put a value on. It is 12.8mm X 11.0mm X 3.6mm. The body tone is around N7-8 and the brightness is B4-5 

If you contact me I can send images of this opal. I've had valuations from £400 per carat to £1,500per carat so I'm really struggling to put a price on it.

[fashunu4eeuh]

With such a valuable gem, it would be worthwhile to have it professionally appraised.