Mexican fire(transperant) opal turns white

[Procer]

Hey pricescope members.

I just bought two mexican fire opals, one rough one faceted, from two different sellers. Both of them has now turned white/milky, the faceted one has turned completely opaque, while the rough only has in one part. My guess is that it is filled with something, like lead filled rubies, and just wanted to hear if anyone has any idea what it could have been filled with? What throws me off is that it wasn't white when I received it, but it has turned over a period of three days time.

-Mathias

 

[Treenbean]

Sounds like it is a hydrophane opal. When soaked in water they turn completely transparent, when left out to dry the turn milky white opaque. Some of these opals are unstable and will crack so people pack them and store them either in water or with a dish of water for humidity.

 

[chrono]

No, they aren’t filled but it does sound like they dried out, which Treebean explained.

 

[Procer]

How very interesting I will immediately put them in water. And I kind a guess I cannot put them in any jewelery...unless I sweat a lot.....which I don't. Joking aside, Thanks a lot This was very informative I will investigate further, now that I have a name.

 

[LD]

Don't completely submerge them. Just put enough water for the gem to sit in. I believe that you can put these in jewellery - they're no different from other opals it's just that you need to water them a bit! Other opals like to be worn because the moisture from your skin helps to keep them hydrated!

 

[whatmeworry]

I wonder if you could post pictures before and after hydrating. Curious to see the difference

 

[PrecisionGem]

This sounds kind of weird. Normally the orange and yellow Mexican opals don't turn milky when they are dry. In fact you should only buy them after they have dried out for many months. The Ethiopian opals do turn milky color when they are wet, but once dry clear up again. I started to cut one just yesterday, it was totally clear when I picked it up, but after pre shaping it some, it's a milky white and no longer transparent.

I've cut a lot of Mexican fire opal, and have never seen this effect on any of them.

 

[Procer]

oh yea sure. I will leave you with these pictures of the stone after hydration, when it has dehydrated I will take more photos. This is to my best knowlegde mexican fire opal(I am starting to doubt myself after reading PrecisionGem comment). Both the rough and cut stone has a lot of flashes, both in red, green and as hopefully captured, purple. The flashes is of curse more apperant in real life, and even more so in natural lighting(it is early evning where I am, but pitch black). The weight of the faceted one is 1.55ct and is a stepcut octagone. The rough is 4.85 ct and as you can see it has a bit of the motherstone on it. Hope this has been informative.





Oh yea and to PrecisionGem, my stone is the other way round, after submerged to water they become clean and transparent, when they dry up, they get milky white.

 

[whatmeworry]

Thanks Procer. This is interesting. Wonder how long it will take to dehydrate?

The Ethiopian opals that I have do the opposite of what Gene described. They are opaque when dry but turn transparent (but not milky ) when wet. One dried out overnight and turned back to the white opaque body color but another one is still translucent some 3 weeks later. Hydrophane opals are interesting.

 

[LD]

I wonder if yours is really from Mexico? I've found some photos of them from Ethiopia with the same body colour as yours http://www.ethiopiaopals.com/brilliant-welo-opalhoneycomb-harlequinmuseum-grade10108.html

Here's some more info on Hydrophanes you may find useful:

From Gemworld.com
"Hydrophane Opals - The precious variety have the ability to absorb water and become transparent. After releasing water they become opaque again. This process can take place within a few minutes of immersing the stone in water or reversing it by removing it from water. This phenomena can take place without damage to the stone and has very little affect on color flash. These opals are some of the most interesting and intriguing. Most of these precious variety of hydrophane opals come from Virgin Valley, Nevada. Sometimes "Hydrophane" refers to opals that are dual until wet with water. These dual hydrophane opals are not considered precious and are usualy found in Australia. "

From Allaboutgemstones.com
"Hydrophane Opal & Cachalong Opal
Hydrophane opal is a highly porous variety with a dull surface luster, that may not display any play-of-color until it is immersed in water. The porous cavities in hydrophane opal can interfere with light transmission, but when these cavities are filled with fluid, light is able to pass through the specimen without interference, although this effect varies with the opal. Some specimens may have play of color all the time, while other ones may have play of color either only saturated or only dry. Many whitish opals from Andamooka, South Australia, and Virgin Valley, Nevada, as well as Welo or Mezezo "chocolate opal" from Ethiopia (aka "Ethiopian desert opal") are examples of hydrophane opal. Due to their porosity, hydrophane opal can be easily dyed to darken their base color. Like the hydrophane opal, the cachalong opal is a highly porous, whitish material that dehydrates, and becomes increasingly transparent as it is wetted, but cachalong does not display a play of color/fire when wet. The color of cachalong opal can range from milky white to creamy white, bluish white or yellowish white. Some extremely beautiful opals from places Nevada and Ethiopia may be discounted by the gem trade because of potential stability problems and fine pieces can end up being kept in water as uncut specimens."

 

[Pandora II]

Those look Ethiopian to me too...

 

[Largosmom]

Those look like ethiopian opal to me. The body colors are clear to shades of golden brown. When dry, they go milky in color, clear when hydrated. You can just wet them with a bit of water and if hydrophane, they will go clear within 10 minutes to a half hour. It can take several hours to several days for them to go back to their dry milky color. When clear, they may lose some or all of their fire. Some retain their fire.

I am not aware of mexican opal having hydrophane qualities...but I'm no opal expert.

Laura

 

[Richard M.]

I've cut a lot of Mexican fire opal, and have never seen this effect on any of them.

I've cut a lot of it too and hydrophane is quite common in precious opal from several Mexican sources. I learned about hydrophane while cutting one: suddenly all the play of color disappeared and the opal turned from whitish to transparent. A few hours later it dried and the whitish color returned as did the colorplay. That's a sort of "reverse" hydrophane, similar to some Ethiopian opal. Some behaves the opposite way too: no play of color until it's hydrated.

Richard M. (Rick Martin)

 

[Procer]

I took them out of the water when I whent to sleep last night( which was right after my message), and when I woke up some 8 hours later, they had gone back to the white stade. I should try some day to do a more scientific eksamination of how long it takes them to switch to white. I did that when i rehydrated them, it took 3 hours for them both to become perfectly transparent(as on the photos). It is only the octagone that turns completly white, and it still has alle its play of color, same as with the rough which only becoms cloydy and spartly whiteish. Here are the photos of them in they "dry" state:





And many thanks to you all and especially LovingDiamonds for the usefull read.

 

[PrecisionGem]

I'll post some pictures of the Ethiopian opals tonight. The one I started to preform has turned white once wet, and is still white about 30 hours later. I'll shoot a rough one that is very transparent, then wet it and shoot it again. Should have these posted by about 9 or 10 eastern time tonight.

 

[PrecisionGem]

This first picture is the opal Ethiopian opal when it's dry.

 

[PrecisionGem]

This next stone is one I started to mess around with over the weekend. It got good an wet, and turned white. This one was similar to the one above on the far right. The dry pictures above don't really show it, but the stones have a very high level of transparency.

 

[PrecisionGem]

I don't really cut this stuff, I just bought a few pieces since I thought they were so interesting. This is the first time I messed around with one, so I have no idea how long it will take to dry out, but I have read it could take a week or more. I'm thinking of just leaving these alone and keeping them as conversation pieces.

 

[Largosmom]

Gene, the ones I cab'd (first learning opportunity!), would be nearly clear in about 30 minutes...and varied on the time it took to dry out. A couple went white in an hour or two after I set them aside, others took a couple of days. I guess it matters on the porosity of the individual stone as to how fast it can absorb or lose the moisture.

Laura

 

[Procer]

first of all PrecisionGem love your photos!! Very crips, very illustrating of your point. The color of the stones, really do look like my opals, and therefore my opals really do look like they are ethopian. Very facinating stuff.

 

[Dubstephero777]

I bought some opals from Ethiopia. I am new to shaping and getting the dirt out of them. When I first started I used just a pick to get it out, now I have a dremel. Some of the pieces I soak in water so I don't shatter them but have noticed when they dry turn milky white. Are they ruined? I better just buy black opal from lightning ridge seems a waste of money for them to turn white.

 

[T L]

I bought some opals from Ethiopia. I am new to shaping and getting the dirt out of them. When I first started I used just a pick to get it out, now I have a dremel. Some of the pieces I soak in water so I don't shatter them but have noticed when they dry turn milky white. Are they ruined? I better just buy black opal from lightning ridge seems a waste of money for them to turn white.

I have a drop dead gorgeous Ethiopian turquoise base opal that I accidentally put a wet cleaning cloth on and it sat On it overnight. Much to my chagrin, that opal and another Ethiopian opal next to it, went transparent!!!! I actually was worried but then I wore them out to dry out on my hand in the sun, and both returned to their former glory. I suppose the peace of mind happened because I always thought that this opal might have been dyed, since it has a gorgeous turquoise background color. Since it turned transparent, that was a good way of testing for dye. If it were dyed, the background color would have remained the same, but there would have been no color play. Before and after photos.

After soaked


after getting dried out