Constellations of Colour - Queen of the Queen of Gemstones, the EMPRESS of Precious Stones.
In 2008 in the high arid mountains of Wollo (Welo) province of Ethiopia a "new" volcanic origin Opal CT (Cristobalite-Tridymite) was discovered. The finest examples of this gemstone are called IMPERIAL OPAL and may be faceted as well as cut in the usual cabochon. They are easily the most rare and most beautiful of precious stones known. Pliny the ancient Roman once called Opal the Queen of gems: Imperial Opal is thus the Empress of Precious Stones. J.D.Sage (Troubadour)
Photography & Comments by Gemologist Gregory Kratch to the Lapidary Journal Editors 2013
You published an article in the Lapidary Journal January/February 2012, on the "new" Ethiopian Opal. As I have been cutting this material for years, I wanted to add some of my own observations and experience with this beautiful and very important new discovery, particularly the opal from Wollo Province. As your article correctly noted, this opal is a Hydrophane Opal formed in a volcanic environment. But the differences in formation and physical structure mean that it is not always comparable to opal formed in a sedimentary manner, as is most of the Australian opal. The descriptions in your article of hydrophane and its reaction to light and production of colour in a dry and wet state I consider incomplete in some very important aspects. While it is true that almost all hydrophanous opal will show brighter plays of colour while wet, upon drying, the sedimentary hydrophanes tend to become duller and duller as they dry and the water leaves the stone, their highly porous and irregular structure continuing to interfere with the transmission of the light and consequent production of a play of colour, until the opal may appear almost opaque with virtually no discernable colour.
Unfortunately the article failed to mention that when the opal from Welo (Wollo Province) begins to lose its water content it becomes more opaque or creamy at first, and then begins to clear over a period of a couple days or weeks, if left in a normal environment in a room at normal temperature as the stone continues to dry out. I would not recommend any forced heat to speed up the drying process. Each stone is different. In this way it is similar to the chameleon opal from Java, also formed in a volcanic environment. The Javanese opal also shows its best colour play when it dries out, unlike most opal from sedimentary deposits that look better when wet. And often, even usually, the new material from Wello is more beautiful dry than wet. In the finer near transparent grades I find the slight cloudiness or turbidity in the cut stones, a slight haziness in an almost transparent base, a slight translucence makes them more beautiful and can show more colour than when fully hydrated and completely transparent. It is similar to what happens when you cut a cabochon of very clear crystal opal and put a very high polish on the back of the stone, the highly polished surface allows the light to leave or leak out of the back of the stone with very little light returned to the viewer except the play of colour. However, a soft even slightly frosted finish on the back like a satin 600 surface, scatters some light and lights up the stone better often giving a better more perceptible colour play. In the best Ethiopian material, in my experience, the stones are actually more beautiful when completely dry with a slight haziness to scatter and spread the light around. The entire stone lights up better. Lower and lowest grades, less transparent or opaque opal may be much better when wet. I have limited experience with material of this lower quality. As always with opal, it depends on the individual stone. They are all different, and that's the charm. Often frustrating, but always interesting. The article failed to mention that this new hydrophane opal from Welo would not react like most others, Java excepted, and after an initial period of dulling, when first removed from water and begins to dry out, would then continue to become more transparent and show a better and better colour play as the dehydration continues.
There were other issues I would like to discuss concerning the description of blacks (I have seen a few as well as some beautiful crystal opal on a natural black skin, sort of like a colour bar over a thin black base as seen for example, in some boulder opal, but probably with an iron and manganese oxide crust in the case of the Ethiopian opal from Welo). And base colour and temperature sensitivity as well as iron content and stability are a whole other discussion. I felt it important to write you about the impression your article left that all hydrophanes are only beautiful when wet and lose their colour when dry. This is certainly not the case with the material from Wollo Province.
With the continuing reduction in production of the Australian fields, this new discovery of opal, and in particular, the new opal from Welo, is rapidly gaining acceptance and market share because of it's pure colour and astoundingly bright colour play, exceptional and unique patterns, and just sheer beauty. The Troubadour and Poet J.D.Sage* has dubbed it “IMPERIAL OPAL” the Empress of precious stones. I concur. We should thus enthusiastically welcome this lovely new addition to the royal family of gem opal, the new Ethiopian Imperial Opal, truly an Empress in this family of the Queen of Gems, as Pliny the ancient Roman so aptly described opal, so long ago.
Please follow links to learn more about Imperial Opal (Ethiopia). http://www.jtv.com/library/ethiopian-opal-gia.html
*J.D.Sage (Troubadour) song "What About Me?" Please follow these links to learn more about J.D.SAGE and hear his music and lyrics. "What About Me?" Video (Preview), http://www.cdbaby.ca, http://www.itunes.com, http://www.amazon.com, www.jdsage.com, Video Promotion and also "Internet Highway Cruising Song" Video
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