I’m curious to know what others would do with these?
They were all listed as fire opals originally, from various locations.
They stay a solid colour, middle one did a day in water, the clear one had a week, they don’t appear to get damaged either way, wet or dried out.
A couple are Contra Luz, but most have no colour inside them at all.
I’ve a dozen or more like it, some yellow and orange ones too, all living in a water container now, and I’d rather have them in display pots.
What would you do with them, and/or am I missing somehing?
I’ve searched online, most info refers to Hydrophane Opals and colour loss due to water either being to wet or dry. I’ve found nothing that matches these stones anywhere.
These do not look to have any particular prismatic fire…so you’d value them as fire opal, but they are not, as someone else said, the right color for fire opal, which is yellow to orange to red in color. The milky ones are just opal base without any fire that I can see, so not worth much. The transparent stone is worth something as a transparent faceted stone, but it is a weak and brownish yellow, so not worth much. I don’t see any contraluz fire in the light that you’ve used to photograph them, so that issue may make a difference in price, but still, I can’t see these being highly desirable. Now if there is some fire somewhere inside them, they might be cut to reveal it, but the chances that the cutter missed that are slim to nil. -royjohn
None of the 3 pictured are Contra Luz, but all like water.
The ‘milk opal’ is a Faroe Island opal, it likes water too, the pic below was taken friday morning.
I just noticed, I got the ‘Milk Opal’ is upside down, in this pic, it has two visible brownish inclusions. It weighs 6.34cts when wet, this morning it’s down to 6.30cts, it could drop a little lower, but it takes little water or time to make it transparent again.
The other is Mexican, it will dry out eventually, but it could take a few weeks. None of them pictured fluoresce under any wave length I have available, 254, 365, 395 or 405mn. UV was one of the first things I tried.
You’re right, there is no fire in any of the ones pictured, you can get orange/red flash from the back facets, but that’s about it. I like how they look, if I could just keep the water content in them, not so impressive being opaque white sitting in gem pots, which was the reason for the start of the thread.
The typical process for opals that come from Queratero in Mexico is to let them dry out for several months or longer on a sunlit windowsill. Those that do not crack or go milky can a be sold. Trapped water molecules have a lot to do with the appearance of opal, and apparently yours do not retain the water necessary to make them translucent and/or give them fire. It is pretty typical for opal to be displayed in jars filled with water and having a curvature that magnifies the stones within. It is also typical for the savvy buyer to ask to see the stones outside the vials of water. Fire opal, the kind with no play of color which is faceted for its color, should be displayed and sold dry for the obvious reason you have seen. I don’t know of any way to seal in the water reliably. I would chalk this up to experience and go on to enjoy other stones and to educate myself further. Ethiopian opal, interestingly, loses its play of color when wet, but regains it when it dries. That’s quite disconcerting when you start to cut one and the fire all disappears! -royjohn
I could experiment with a few bi coloured (orange/white) Mexican ones I have and see if they’ll take it, but it’d be a shame to ruin the Faroe Island ones, I’ve spent most of the weekend trying to find facted ones, not found any at all, cut or otherwise. Very little out there about Faroe Island Opals.
i guess you noticed, I wasn’t particularly savvy when I started this hobby, but learning all the time, reading what I have on opals crazing when they dried out, I was quite surprised this don’t, I’ve dried them out and soaked them a few times. I’ve an orange one that crazed, but it was like that when I go it. But it is fun watching them do it.
Until I find a viable solution, I’ll dry them all out again, put them where they ‘live’, in gem pots. Wait for an other issue with something else
Thank you both @rlynch@royjohn for the suggestion, much appreciated .
These are most likely faceted Ethiopian origin opal. The specific term you are looking for his hydrophane, meaning they are water-loving and absorb water. Unfortunately they will also absorb oils, which will permanently damage them. A much faster reaction can be achieved by using denatured alcohol or acetone, however be careful if you suspect they are dyed because either will damage the material.
They are Hydrophane, but the small white one is from the Faroe Is, the larger one is from Mexico. The Mexican stone is still drying out, but the Faroe Is one only took two days, and it dropped in weight from 6.34ct to 6.29ct, if my math is right, under 1% weight difference, not a lot of water to take it from opaque to transparent.
Still, neither show any colour, so no good for jewellery, but fun for a collector to play with
That requires a bit of discussion. A very large fraction of opal from Australia has low water content and doesn’t lose significant water under normal circumstances. Remember that the Australian opal fields are in the desert. Really fine opals are kept in bank vaults which are just big dryers. They don’t crack or craze from the loss of water. Of course, one needs to look into storing good opal in such a dry environment. What that means is to keep an eye on it outside of the vault for a few months. If it hasn’t crazed by then, it never will. Lightning Ridge has many fields. Most yield opal that is completely free from long-term cracking. However, there are some fields that produce stones that crack on drying. Frog Hollow is one of the. After a few months above ground, they tend to crack. Other stones have been sitting in museums in a dry environment for over a century w/o displaying any cracking.
So, while it’s true that opal will lose water, even if the amount is small, it still makes the stones susceptible to absorbing oils and soap. Moistening them will make them less susceptible to getting dulled if you, say, accidently stick them into soapy water.
If you dunk them occasionally in clean water to prevent possible contamination, that fine. If you need to dunk them to prevent crazing, then you’ve got a specimen, not a gem.
