Yellow Opals?

[Cave Keeper]

Is there really such a stone called Yellow Opal?

Some Chinese are selling as Yellow Opal what they claim is Yellow Jade, which can form another puzzling topic: What is Yellow Jade?

Then there are some people claiming there Dendritic African Yellow Opal.

There''s also some form of Yellow Opal, supposedly from an American state.

 

[valeria101]

There are som yellow opals - the Mexican sort - with no play of color (other than totally by coincidence). And then opal is a common mineral - you find lots of non-gem sorts with smooth texture and pastel colors sometimes suitable for carving, sometimes not even that (they can be unstable or badly fractured to begin with).

You might find such opal sold as lapidary material here and there: white (some from Turkey is better knows, but otherwise there are hundreds of locations for opaque white opal - thatis the most common kind), green (Macedonia, Turkey), and yellowish (not a bright yellow, no idea where from) come to mind as the usual possibilities. Any can be died rather easily.

Large chunks are sometimes available. That and the nice texture recommends the material for carving in the first place. So I could think of that being used for similar things as jade - small carvings.

Perhaps the guys you met were shy of dieying opal green and selling it as ''imperial jade'' and used some yellow instead. The color cold have been natural.

There is always some question about the stability of these opals: they craze and crumble as they dry out. I wold thinkthis is why they are not more popular despite being rather attractive. Some are known to be stable, but there is no telling first hand!

 

[Richard M.]

Cave,

This is an image of a 24 carat piece of rough facet-grade yellow opal from Idaho, U.S.A. I have images of faceted stones but can''t post them. Somewhat similar material comes from Oregon and Nevada and probably elsewhere but the Idaho material is well known.

Yellow opal, including dendritic, comes from Tanzania in Africa and from Brazil. Most I''ve seen is cabochon and carving grade. So does an interesting cat''s-eye type of opal that occurs in yellow and other colors, from white to black. It cuts very sharp eyes. I''ll post an image when I have more time. There''s one in the archives somewhere I posted a year or so ago.

It''s important to distinguish between common opal with no play of color and precious opal which always has play of color. Play of color depends on the arrangement of spherules that make up opal (it''s hard to fully explain in 3 paragraphs!) Common opal (or potch in Aussie terms) can occur in nearly any color from white to black. Fine pink and blue-green common opal come from Peru; green and blue-green from Macedonia; blue and many other colors from Idaho, Nevada and Oregon; orange, red, yellow and even black from Mexico, etc. For those who want to learn about opal there are many good books but I recommend Fred Ward''s "Opals" as a good place to begin.

Richard M.

 

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Author: Richard M.
Yellow opal, including dendritic, comes from Tanzania in Africa and from Brazil. Most I''ve seen is cabochon and carving grade. So does an interesting cat''s-eye type of opal that occurs in yellow and other colors, from white to black. It cuts very sharp eyes. I''ll post an image when I have more time.

Here''s a picture of what I think you''re talking about, from AJSgems... I''ve always thought these looked cool, but wasn''t sure what they were because they''re referred to as "opalite" on that site.

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[Richard M.]

Hi Widget,

"Opalite" is a name often used to describe impure colored varieties of common opal like red cinnabar-infused Myrickite. It may be applied to the cat''s-eye material (I''ve heard the name used) because of the inclusions that create the chatoyant effect. Unfortunately Opalite''s also the trade name for a man-made precious opal simulant from Asia and also for a type of glass that''s been used in cheap jewelry for many years.

The image you posted appears to be natural African material. The color is typical and the wavy "eye" indicates an imperfection left by nature and not by a lab. I have some beautiful pieces of this material in near-black, light yellow, reddish-brown and white. It''s an interesting curiosity and some pieces look very much like natural chrysoberyl cat''s-eye.

Richard M.

 

[valeria101]

One more of the same...

from Customgemstones

I have never seen white cats eye opal. Any chance for a picture ?

 

[Richard M.]

Date: 8/25/2005 8:06:45 AM
Author: valeria101


I have never seen white cats eye opal. Any chance for a picture ?

I should have said "whitish" or "silvery." I was describing the colors from memory and while my color memory is good it''s not perfect.

Since I still haven''t learned how to stitch images together I''ll post images of three pieces of cat''s-eye opal rough. I''d describe this first as "whitish."

 

[Richard M.]

This one is silvery to my eye.

 

[Richard M.]

This rough is a pastel yellow. The material is mined in a wide range of colors but these give an idea.

 

[Richard M.]

Sorry -- the last two are the same stone which I posted twice by mistake. It photographed much less yellow than it really is and I brought it to the computer and matched actual color digitally.

 

[valeria101]

Thanks for the pictures.

Have you cut this material? It looks quite intriguing.


BTW, I could not agree more that color correction is helpful.

 

[Richard M.]

Date: 8/26/2005 12:32:21 PM
Author: valeria101
Thanks for the pictures.
Have you cut this material? It looks quite intriguing.

Some time back I cut some test stones but I have higher-priority cutting projects. I''ll cut this for fun if I ever have the time. It''s really a collector/curiosity gem because genuine chrysoberyl cat''s-eyes (including alexandrite) are now available at reasonable prices for smaller stones. Cat''s-eyes have never gained wide popularity here in the U.S., I think because very cheap cat''s-eyes made from bleached tiger''s-eye quartz, mass-produced in Idar-Oberstein, have diluted the market. It''s Gresham''s Law applied to gems: Bad money drives out the good.

Richard M.