Cutting a blue pea nobby opal

Uncovering a beautiful black opal from this blue pea nobby? Yes pea-lease!

Pea nobby?! Is that some sort of crude joke?! Thankfully not.

A pea nobby is a spherical rough opal that can be formed in potch or full color. You can find black, dark, white, or crystal opal in pea nobby form and they can have clean or rough skin.

This pea nobby opal has a beautiful blue-green color bar and potch on the back; both good signs. On the downside, the rough skin makes it hard to see if the color will be watery, which is not what I’m after. I like my opal how I like my coffee; full strength!

The first step is to study the opal. Where does the color bar go? Where does the sand go? Could it turn black?

I make an unfortunate discovery after grinding away at the sides to see inside the pea nobby better; this opal has unhealthy potch. Unhealthy potch is dangerous to leave on your gem because it puts pressure on the healthy color of the opal and could crack. I spoke about healthy and unhealthy potch in this video a few weeks back so head there if you want to learn more.

I have to grind all of this cancerous potch away otherwise it could crack. Under this cancerous potch, I can see that this opal has color on both sides with black potch inside; a very cool discovery!

Polished and pretty, this black opal has a medium dome and weighs 1.30 carats. With gorgeous deep blue almost purple color and flash of neon, this black opal would make a stunning ring stone.

Thanks for watching and I hope you learnt something!