Help with new opal ring

[RSargent]

I bought this at a gem show in Creede CO. I love the handmade 14k setting, and the opal (I was told from Australia) has amazing flash of color in most light sources and some neat patterns. The setting has an open back with a protecting bar across it, and the back of the stone shows a brownish-grayish color but is clearly the same stone.
My questions is, would this be called a black opal or a white opal?
Thank you for helping me.
-Robyn

 

[Bex]

I think it's a boulder opal, not a black or white. Especially if the rock on the underside is clearly part of the stone, vs an attached doublet backing.

 

[RSargent]

Thanks Bex. The stone is opaque and one color on the back. Just not showing as much color --but some. I can see through the stone when the light comes through the back.

 

[katharath]

What determines a black or white opal is the base color, and while it doesn't actually need to be "black" (I have a black opal that is actually a dark blue base/body), it does have to be dark. Basically a dark base with color play flashing across it. IMO this one would have to be considered white.

My black opal is lightning ridge, and it does have a tiny bit of matrix on the back, so I'm wondering if this is what you're referring to? If it's like mine, it's definitely not a boulder opal, but does have a tiny extra bit of rock on the back. Not sure how to explain it, I'll post pics. It would be easier if you could post a pic of the back of yours, but I don't think it's really necessary. IMO on yours, assuming it's not a boulder opal (sounds like it is not going by your last post), I'd have to go with white.

Quick pics - sorry so short. I'm running out the door after I post this, lol! Will check back later though...

Front pic then back pic of mine - literally just snapped the back pic so not a great one but best I could do, HTH.

Eta - also meant to say you have a lovely ring

 

[GliderPoss]

It's a beautiful ring! I agree with Kath, it's more about the base colour and I too would guess yours is white. I have a lovely solid black opal from Coober Pedy (forgive the awful iphone pic!) which also shows the back of the stone like yours but it can be difficult to tell once they are set in jewellery. Enjoy wearing your wonderful ring.

 

[katharath]

Oooh HotPozzum I love your ring!!! I want it, lol!! Thanks for adding your pic

 

[aussiejamie]

Can you post a pic of the backside of the opal if you can?

AJ

 

[RSargent]

Thanks everyone! Yes. I will photograph the back and send it soon. The base color is brownish -- so I now agree it's probably a white opal with lots of flash.

 

[chrono]

The POC leads me to think it might be considered a black opal but I'm not all that well versed with opal.

 

[RSargent]

Thank you Chrono. What is POC? I should know but I don't...

 

[chrono]

POC = Play of colour.
Yours looks neither black nor white to me. I wonder whether it falls into this strange category known as Dark or Semi Black Opal?

 

[katharath]

POC = play of color, meaning the flashing colors that an opal displays.

But respectfully, I have to disagree with Chrono. The POC doesn't determine whether an opal is black or white; the base or body color is what determines this. Here's a link to a page that has a lot of great info:

http://www.opals.info/base.php

I'll copy and paste it here too. It's easier to read on the link though, as it's broken up a bit better. It's a good read though as it gives a lot more info than just "black" or "white" opal.


BASE COLOR OF AN OPAL

The term "base color" is often confused but it is really very simple. Think about looking at an opal and extinguishing all the fire colors coming from it. What remains is the base color of the stone. Base colors, sometimes called background colors, include black, semi-black, crystal, semi-crystal, white, gray, blue, orange, brown, boulder black and boulder brown. Base color is one of the four primary characteristics which determine an opal's value.

Base color of an opal is determined only by looking at the top of the stone. With your eye above the stone, look down at the face of the opal as it rest on your table. Notice that it has two color characteristics, the play of fire and a general base color. It is the general base color we wish to determine now.

Base color is actually a combination of three things: color or hue, body tone or saturation's, and transparency or clarity. A complete description of a stone requires mention of all three and each affects the stone's value.

Black Opal
A natural solid opal which is opaque when viewed from the top of the stone, and which has a play of color against a dark background graded as at least#3 Black on the Lightning Ridge Miners Association Tone Scale, is graded as a black opals. The back of the stone may be any color.
Black Crystal
A natural solid opal which is translucent to transparent with play of color which when viewed from the top is graded as at least#3 Black on the Lightning Ridge Miners Association Tone Scale.
Semi-Black
A solid opal which is translucent to opaque when viewed from the top and which has a play of color against a dark gray background corresponding to semi-black on the Lightning Ridge Miners Association Tone Scale.
Boulder Black
A natural boulder opal which has a play of color against a dark opaque background graded as at least #3 Black on the Lightning Ridge Miners Association Tone Scale.
Crystal Opal
a solid opal which is transparent showing a play of color and no base color.
Semi-Crystal
A solid opal which is translucent showing a play of color and a clear base color.
Gray Opal
A solid opal which is opaque or translucent showing a play of color on a gray base corresponding to the gray tones on the Lightning Ridge Miners Association Tone Scale.
White Opal
A solid opal which is opaque to translucent showing a play of color on a white to off-white base color as graded as a white opal.
Light Opal
In Australian, opal graded as crystal, semi-crystal, white or gray are all under a general category called "light opal."
Orange Opal
A solid opal which is translucent to opaque showing a play of color on an orange background. This type of opal would be called red opal or yellow opal depending on the base color.
Orange Crystal Opal
A solid opal which is transparent showing a play of color on an orange background. This type of opal would be called red crystal or yellow crystal depending on the base color. This is generally referred to as fire opal.
Brown Crystal
A solid opal which is transparent showing a play of color on a brown base color.
Jelly Opal
A solid opal which is transparent showing no play of color, but it may show an opalescence without a pattern. The orange material without a play of color from Mexico is frequently seen in faceted stones, and would be termed orange jelly, although it is also called fire opal in the industry. The blue jelly from Australia is sometimes called blue bottle potch.
Blue Opal
A solid opal which can be translucent to opaque with or without a play of color on a blue base color. The opaque blue common opal from the Andes is just call "blue opal." There is also a pink variety of this common opal.

 

[chrono]

K,
I'd like to clarify. I did not mean to say that POC determines the type of opal although looking back at my post, I can certainly see how easy it is to interpret that as though I implied it. This is what I get for typing on the run and using minimal words. When I look at the opal as a whole and the POC, I am looking for the base colour. There is no white base to be seen anywhere. At the same time, there is no black base either. All I see are green and blue, which are the POC. In between all that is small bits of gray. Where are you seeing the white base? Doesn't it need a white base to be considered a white opal?

ETA
In your initial post, you called it a white opal, which I strongly disagree with. In your latest post, you called it a gray or semi-black opal, which I agree with.

 

[katharath]

I meant to say this earlier and forgot - the reason I stated that I didn't think that seeing a pic of the back of the opal was important, is that the opal's value and I believe it's "category" (i.e, black, white, etc) is determined by viewing it face up (although I'm not sure how they factor boulder opals into this? And obviously a backing such as a doublet will affect value too, a great deal in fact).

If we are going by what we can see in the one pic that we have, the base almost looks gray to me. Going by the chart I posted it would actually be a gray opal! But that's just my opinion.

I've done a lot of reading on opals over the last few years, and I have collected about 6 or so; it's difficult because I've found a lot of varying info out there. Opals can be very confusing, they're not like diamonds with a universal grading scale. Opals are much trickier IMO!

(Edited to correct spelling/grammar)

 

[katharath]

K,
I'd like to clarify. I did not mean to say that POC determines the type of opal although looking back at my post, I can certainly see how easy it is to interpret that as though I implied it. This is what I get for typing on the run and using minimal words. When I look at the opal as a whole and the POC, I am looking for the base colour. There is no white base to be seen anywhere. At the same time, there is no black base either. All I see are green and blue, which are the POC. In between all that is small bits of gray. Where are you seeing the white base?

I just posted as you were posting this one; I think my last post probably answers your question. What I'm seeing once I get past POC (which looks lovely, btw!) is gray. The reason I chose "white" opal earlier is bc I thought "gray opal" was a bit confusing, although I don't think it's a true white - I just don't see it as being a black opal at all, honestly. If white and black were the only choices, I'd have to go with white.

Again, this is just how I interpret what I'm seeing.

 

[katharath]

K,
I'd like to clarify. I did not mean to say that POC determines the type of opal although looking back at my post, I can certainly see how easy it is to interpret that as though I implied it. This is what I get for typing on the run and using minimal words. When I look at the opal as a whole and the POC, I am looking for the base colour. There is no white base to be seen anywhere. At the same time, there is no black base either. All I see are green and blue, which are the POC. In between all that is small bits of gray. Where are you seeing the white base? Doesn't it need a white base to be considered a white opal?

ETA
In your initial post, you called it a white opal, which I strongly disagree with. In your latest post, you called it a gray or semi-black opal, which I agree with.

Not trying to be confusing here; every time I post there is either a new post or an edit to respond to, lol!

Again; yes, I called it "white" earlier because the OP asked for a designation of one or the other. Many people sort of categorize them as one or the other because they don't realize that there are degrees other than those.

But yes, to be specific and technically correct, based on the pic that we have, I would say that "gray" is probably more accurate; however to the layperson who doesn't know of gray, I'd call it white over black if I had to choose one. I don't agree that it is semi black; to me it just does not look dark enough to be considered that.

If we have an opal expert here who would like to overrule that, I'm happy to learn . Please share anything we might be missing!

 

[RSargent]

Thank you everyone. Maybe it's brown opal, although the brown is more beige and gray. I can see through the stone from the back and there is no sign of matrix. The play of color (POC, I learn something new every time I visit here!) is really something. I have never seen such flashes in person in an opal, but I haven't seen that many opals either. Looking at it makes me think of the northern lights. The colors are saturated and ever moving. Here is another picture that had on my phone.

 

[katharath]

Well, honestly I just don't know what else to add except that it's a beautiful opal! I'm not sure how to categorize it exactly (at this point I'm all categorized out, lol!). What I do know is that it's lovely, I'm sure it's fun to wear and enjoy. Thanks for sharing, regardless of what color is it

ETA - I like your comparison to the northern lights. I lived in Alaska for @10 years and saw them often - I don't miss the snow but I do miss the light shows! Maybe that's why I like opals so much too

 

[RSargent]

You don't need to add a thing. You've been a fountain of information and I thank you!!!

 

[aussiejamie]

Hi RSARGENT,
Your opal looks to me to be a crystal opal or semi black in the n7 base color range if it has potch on the back. A crystal opal is an opal which has no 'potch' on the back of the gem. This can sometimes make the stone abit grayish looking in certain light conditions. If you hold your ring up to the light you will notice that the stone will be quite translucent if viewing through the stone to the light. On black, semi black and most white opals there is usually a layer of common opal aka potch left on the back of the stone to give the stone a base color for the Play of Color to act against. However sometimes there is no common opal on the rough. When this happens the stone is then cut as a crystal opal. This is why I asked to see a pic of the back of the gem. It would be good if you could put a pic up still of the back.
AJ

P.S. It is the color of the common opal or 'potch' on the back of the gem which determines whether the stone is a white, semi black or black opal. Black is preferred as it makes the POC standout more than against lighter colors. It is like watching a movie in a well lit room versus a dark room. The movie looks more vivid in the darkened room.

 

[RSargent]

Thanks Aussiejamie! Really good info. Here is the back of the opal. I think it is an N7 based on what you said, or a crystal opal. I hope the little crack like inclusions are okay (at the top). They don't reflect light and they don't show on the front of the opal at all. Notice the little brown cavity like things too. Is that matrix?

 

[aussiejamie]

Hi Rsargent,
I would call your opal a semi black opal approximately n7. The little brown cavity looks to be a bit of a sand cavity as the material these opals form in is very sandy/sandstone like. Those lines look like just being potch lines / webbing which is not a big issue if its not on the face. It does not effect the sturdiness of the stone. Hope this helps!

AJ

 

[chrono]

Glad that it seems to be a semi-black opal from a resident Aussie rock hound and that the lines aren't cracks.

 

[RSargent]

Thanks so much Aussiejamie. Your help was as big as Australia! And many thanks to everyone who pitched in to help me in this thread. Love you guys! I am happy to have such a lovely semi-black!
-Robyn

 

[aussiejamie]

No problems guys!!!! Always glad to help when I can and it is a beautiful gem you have.

AJ

 

[abbit]

*DROOLS* That aqua color goes so well on the dark