"Why is black opal so expensive?"

[kenny]

 

[Bron357]

Thanks Kenny.
Mining Australian black opal is hard work. They can’t mine in the summer months because the temp can go over 45C, that’s over 110 F. It’s also very dangerous. The mining is done deep underground and ”cave ins” aren’t uncommon.
The clay that holds the opal is just like concrete. They can’t go recklessly using a Jack hammer or explosives because the opal will shatter. So it’s slow careful picking, chipping away. Then even if the do find a Nobby or seam, it may not contain colour. The colour only develops if the material contain Silcon spheres that have “grown” large enough and undisturbed to refract light.
unlike many other gemstones where there can be indicators in the bedrock, with opal is just “hit or miss” and there’s a heap more “miss” than “hit”.

 

[LilAlex]

"...get rid of the debts I have..."

And after 45 years, that qualifies as "doing good, not great."

 

[Jambalaya]

Thanks Kenny, that was really interesting.