What Is A Black Opal ?

by Bill
(U.S.A.)

Question: What is it exactly that distinguishes a black opal from other opals ?

Can an opal be dark and not be a black opal?



Answer: If opal sits on a black base, it is classed as a "black opal".
If the opal sits on a dark grey base then it may be classed as a semi-black opal.

A lighter grey base would class it as grey opal.

True black opal is the rarer of the species but the value naturally depends on the quality of the gem opal.

Rare patterns make them even more valuable e.g. harlequin patterns with primary colors of red, red with royal blue and so on. (My carved Black Opal Pendant is a natural black opal without any backing.)

What should matter to the consumer is the quality of the opal with the clarity and play of it's gem colors, whether the base is black, semi-black, grey or crystal then becomes a matter of choice for the individual.

One may have a black opal with average gem color compared to the same sized grey base gem stone that has brilliant gem color - the grey based gemstone would win hands down i.e. much more valuable because of the quality of the gem opal.

Other factors come into play e.g. intensity and brilliance of color followed by the base tone which goes from black (with it's sliding scale from N1-N4 etc.) then semi-black, dark grey, grey and light-grey to white.( N5-N9)

Top gem crystal is a different category again.

At the top of the scale is the finest black opal; it is rare and can range up to $50,000 per carat (for larger and very rare patterned brilliant gems).

Next on the price scale would be the finest gem crystal opal.



Question: Is black opal more valuable because of the definition that has been attached to it, or are there practical issues?

Answer: Yes, it is more valuable because of the base it is attached to when mined, and the practical issue here is that the natural black backing intensifies even more the brilliance of the colors.

It is a rare occurrence having quality gem opal forming with the natural black base stone. Hence the price tag!

(If the opal gem bar in black opal has been cut or removed from it's black base, it can no longer be classed as black opal. A highly unlikely and insane thing to do!)

Question: Is geography a factor ? Does the opal need to be from some particular region to be called a black opal ?

Answer: No, geography is not a factor - black opal is classified by it's black base wherever it is found.


Question: Comparing two opals, both with comparably dazzling color flashes, why is a true black opal better - because of the base it is attached to when it was mined ?

Answer: Yes


Hope these answer your questions for you !

Regards Peter