Take a look at this stone. What do you see inside it? Probably you are observing a seabed, or maybe it is just someone’s aquarium? Actually, this is nothing but an Opal – a commonly known gemstone, more accurately so-called Oregon Opal, obtained from Opal Butte, located in Oregon. But how the Opal could contain a “piece of the ocean” inside it? It looks like the nature itself has taken an effort to create this unusual gem at the beginning of time.
Perhaps, we wouldn’t be able to find any gemstone, which could boast such magnificence and attractiveness from one side and such mysteriousness and inscrutability from the other side, which could be similar to the Oregon Opal.
Just gaze on it again. It seems like that the sunbeam helped to uncover the entire splendor of underwater life. We can enjoy the diversity of oceanic nature inside this Oregon Opal. There are the corals, the fish, the air bubbles of different colors, the sand, the rocks, — everything that the diver could watch.
Take a look at another specimen of the Oregon Opal. Isn’t it an eruption of the underwater volcano inside it? Could you see the lava or botryoidal structure, or this is just the bubbles of caviar?
Our mind is drawing the unusual pictures, when we look at any of the Oregon’s Opals. But, probably, we are right, assuming that the pictures, we are observing, are the “sketches” of the creator of the universe. Let’s figure out!
Opals from Butte or Opal Butte Mine
The Opal Butte deposit, where the Oregon Opal first was discovered, was the private property in XIX century. In spite of the fact that the mines produced the diversity of the opals and agates, they have been closed, due to the lack of appropriateness of further development.
The gemstones, obtained on the Butte mines were in insufficient quantity, and, therefore, the mines haven’t possessed commercial value. Nonetheless, there are the evidences that some splendid opals from the Butte mines passed into the possession of private collectors.
However, subsequently, the mining of these deposits has been developed by the “West Coast Mining” company in 1987.
Oregon Opal – what is it ?
Oregon Opal owes its origin to the Columbia river, flowing in northeastern Oregon, whose rhyolitic volcanic flows were formed in the early Tertiary period, lasting from approximately 65.5 million to 2.6 million years ago, according to the Encyclopedia Britannica.
The so-called “thundereggs” or “geodes,” in which Opal is formed, occur in amorphous volcanic glass, known in geology as a perlite. The perlite, in turn, eventually, turned into a pastel clay, whereas the thundereggs are found solely in clay area. Thus, the transformation of the perlite is related to the Oregon Opal’s origin.
The thundereggs, containing opal are quite rare, thus only 10% of them contain the opal suitable for jewelry purposes and only 1% of them contain known to us so-called Oregon Opal. Furthermore, the only small thundereggs contain Oregon Opal, whereas the bigger ones are usually contain the common Opal.
Such specimens of Oregon Opal as we seen above are quite rare, thus, each 220 pounds obtained annually contain only 10% of gem quality opals with splendid play of color (according to the data of 1987-1988).
Stability of Oregon Opal
The peculiar feature of the Oregon Opals, obtained at Opal Butte, is the extremely instability. Many specimens, under the influence of the sunbeams and dry air are beginning to crack, therefore the Oregon Opals are tested before selling.
This peculiarity is due to the existence of the water inside the Oregon Opal’s crystals, hence, when the sun and dry air affects to the geode, the water begins to vaporize irregularly, thanks to layering structure of the geode, whereupon, the crystal of Oregon Opal begins to crack.
Thus, the suspected specimens leave for 2 months at room temperature in a dry room. If these specimens don’t craze, during this period, then they are suitable for selling. Moreover, the results illustrated, that 95% of Oregon Opals, passed this test, are capable to save their resistance to cracking for years.
Our small research helped us to figure out where the Oregon Opal has been obtained, how it was formed and why it possesses such significance for the scientific and jewelry world.
Let’s sum up the facts, concerning the Oregon Opal:
- Oregon Opal is mined in Morrow County, south of the town of Heppner, on the peak height of 4700 ft, called “Opal Butte;”
- Oregon Opal is of volcanic origin, it occurs in geodes or so-called “thundereggs,” that are occuring exclusively in clay area;
- Oregon Opal has been formed in the early Tertiary period, that was 65.5 million years ago;
- Oregon opal is quite rare, due to the fact that only 10% of the stones, obtained at Butte Mine are suitable for jewelry purposes and only 1% of them possesses such magnificent play of colors;
- Many specimens of Oregon Opal are apt to craze, and, therefore, are tested before selling.
Take a look at the Oregon Opal again. Probably now you can realize how much time and effort the nature spent to create such distinguished and magnificent gemstone as the Oregon Opal. Thus, it’s perhaps a real “sketch” of the creator of the universe — who knows? By the way, the Oregon Opal, containing Nebula inside it, has been sold for $20000. May be this stone has been a “sketch” of the Creator, when he created the universe?
- Images: Thanks to Inna Gem – Your finest source for Ethiopian Opals
- George F. Kunz – Precious Stones (1893)
- Opals from Opal Butte – GIA