Bolder black opal in matrix balue

Hi what could the value of the opal colors be in this black bolder opal. It is 3 and a half pounds. It is a ex measeum piece someone bought at a estate sale and sold to me on Etsy. I mean the colors that you can see. In the sunlight it has play of color and looks very translucent opal.


I looked at your photos. Nice boulder opal there. Yes, I would say it is a nice collection item for a display. It does look to have a nice play of color. Not sure what you paid for it. Usually, when made into jewelry, you keep enough iron stone around the opal to present it in wearable fashion. It is hard to say the exact value, as it is unknown exactly how much opal is present in this stone. I would consult the price tables and take to 1st level of price.

Thank you! I paid around 300.00 usd for it. It is expensive but very pretty.

I would agree with calling this boulder opal, and a good cut boulder opal could be worth good money, but I don’t think you can call this black opal, because some of the base color that you can see is white. What might happen when/if this is cut up, IDK. Perhaps there’s an area in it that has a completely black body color, perhaps not. I’m seeing some white and some dark blue. That said, realy good boulder opal when cut can be valued in the thousands of dollars per carat., rivaling the price of black opal. You would need help from a really expert cutter to cut the opal and the boulder base out of what’s purely a rock with no opal in it and fashion it into something that could be used in jewelry or for display as a cut stone. Also bear in mind that if there are fractures in the opal, in a cut stone the value goes essentially to zero. So there could be fractures in it now or fractures caused by how it is treated which could reduce its size (having to cut out fractures) and value. Regards, royjohn

Thank you so much for all your info!

Hi, well there may be some blue and green colour coming through but not much, most of what is in the photo’s is called potch opal which does not display colour, It seems to be a reasonable sized piece so maybe there is colour going further into the boulder. Black opal only comes from Lightning Ridge in Australia and not from Boulder Opal which comes from a completely different State in Australia. thanks.

Hi I have a question. There seems to be flashes of color when moving the opal and found in the sunlight. Would that count as play as play of color? Or would that cost less per carat because of maybe being called a weaker play of color? Thanks

Looks like a nice specimen but probably not worth trying to cut. The blue color here is the least valuable and it looks irregular, meaning it would be difficult to cut to a standard cab. My suggestion would be to display it on your bookshelf. Not sure what specimen boulder goes for these days but what you paid for it seems reasonable.

The flashes of color you see is play of color. Yes, there is weak play of color and strong play of color and everything in-between. Reds tend to be the most valuable play of color because it is rare in a strong, rich red. Blues and greens tends to be the least valuable because they are the most common. If you bought this piece because you are love the specimen of both potch and precious opal and how this one clearly demonstrates how opals can form, you did very well. If you thought you could have it cut for jewelry and make money, not so much. Beautiful and interesting specimen!

Thank you for all your info! I see what you mean. Weak play of colo r is not as costly. Potch is according to the he internet not worth anything alone. I see tons of flashes of color in the sunlight. I don’t think I would have much potch. But I do have alot of weak play of flashes of color in the sunlight every where about that I can see. So I guess I am saying at many places. Thanks again