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Common Opal / Opalite???

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christopherl1234
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« on: January 03, 2011, 12:58:26 pm »

I have been searching for the difference between common opal and opalite. What I have found so far is that common opal is basically opal without any fire/color play and can come in many colors and inclusions. I also found mention that the word opalite was a trade name for a man-made opal-like stone.

The point of confusion for me is that in other places I find different explanations of the differences. And these explanations seem to describe the material I have as both common opal and opalite. The material I have appears wet when broken, seems to have formed in volcanic tuft or ash, found in shades of green, tan, white, bluish, peach/red, and is dendritic which matches some descriptions of opalite.

But it also breaks into tiny pieces when hit, is soft like opal, a knife will scratch it, is brittle, and it sure does cut  and look like every bit of opal I have ever cut except there is no color play.

So can anyone help me because I am having trouble figuring this out. The information I have found seems to indicate that the material I recently found is opalite...until I get the parts that say opalite is hard and cannot be scratched with a knife and that it does not have a tendency to break into tiny pieces when hit with a hammer.

Furthermore, what I have found also describes what I have found as common opal....until I get to the part where it says that opalite is found in volcanic ash/tuft and forms in ridges


help,,,,
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« Reply #1 on: January 03, 2011, 03:28:31 pm »

Chris, the reference is confusing for sure. And has been so since the man made "Opal glass" also sometimes called "sea glass"

I have some rough if i can find time i will take a few shots so you can see the material in question the reference is most likely referring to. That is if its online and published less then 15 years ago.  However there will be online deniers because the term started at the same time the internet did, and there are magazines from the same period that refer to it as well. But....

The material you have collected and posted i would call as you have. 'Dendritic opal'. If it didnt have the dendrites, i would call it opalite.   This would be a good place to start a list of all the opal names there are, im sure allot can add.   Here is how i see it in three main groups.

Precious Opal* (any color opal with play of color, aka FIRE Also called Fire Opal, or any opal with fire.)
Jelly Opal* (Any color opal, usually clear with no color, but Blue and Red can be common, sometimes called Crystal Opal which is also used when referring to some precious opals too)
Common Opal( Any opaque color opal in massive form with no fire. This is i also call the organic opal because often you find this type in wood replacements. Its the type most opals fall under and the term opalite is often used to describe it.


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« Reply #2 on: January 03, 2011, 03:43:41 pm »

 "Another imitation is a stone made in Hong Kong and sold under the trade name Opalite.  The first time I saw one of these stones I thought it looked exactly like excellent Mintabie crystal.  But then I picked it up.  It was light as a feather (specific gravity of 1.20 versus natural opals of 1.99 to 2.25).  I twas obviously also very soft (about 2.5 on the Mohs scale rather than 5.5 for natural opal)."...
..."Because of its natural look, Opalite could be passed as natural opal."
- Paul B. Downing, Opal Identification & Value, Copyright 2003/2007
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Common opal is sometimes referred to as Opalite, and over time it has become known as such, but most commonly, you'll hear the term "potch" used for colorless opal.
Precious opal doesn't necessarily have to have fire.  Peruvian pink opal is an example.  There are different grades and different prices for it.

Opalite, at a hardness of 2.5, would certainly be able to be scratched by a knife.  Most opal I've worked with can't be, or if it can, it takes a lot more pressure than I've ever wanted to try on it.  I generally use a utility knife to scrape the wax residue off the bottom or top of opals when I clean them up, and haven't ever run into scratches (otherwise I wouldn't do it).

I think primarily the confusion you might see based on websites is that Opalite is a term that has been mistakenly applied to potch.

But then, who knows the origins of the word "potch"? (rhetorical question)

On the opposite end of terminology, "fire opal" has become more associated with the Mexican opal that is red in body tone, not just with color play.

Marketing and industry standards vary, so terms get muddled.

For some good information on opal, see http://www.opalsdownunder.com.au/learn-about-opals
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« Reply #3 on: January 03, 2011, 05:05:36 pm »

Chris, kind of sounds like we have some differing opinions, and you have generated a mild discussion.
What I have been told, when I asked the same question, is that common opal, is of one color and 'mostly' opaque. Opalite was of different colors, mixed in layers or such. The accuracy, sounded good to me, and has held up, when I questioned a certain material.
When I have asked about material, like what you found, it was always called 'dendritic opal".
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« Reply #4 on: January 03, 2011, 06:12:29 pm »

I don't know what is correct but the terms opalite and common opal are pretty much used interchangeably to describe any opal material without fire.  I have some lace opal (looks a lot like crazy lace agate but it is a common opal).  Maybe not that common.
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« Reply #5 on: January 03, 2011, 06:29:05 pm »

Ah.....potato.....potato........tomato.........tomato......... dunno
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« Reply #6 on: January 03, 2011, 06:37:39 pm »

Yeppers Steve!
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« Reply #7 on: January 03, 2011, 07:15:28 pm »

To get a knife to scratch it I had to put a lot of pressure on it. Way more than I ever would on some precious opal. I also have scraped wax off the back of an opal with no problems but doing that uses considerably less pressure than what I had to use to scratch the dendritic opal I found.
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« Reply #8 on: January 03, 2011, 07:23:04 pm »

Ah.....potato.....potato........tomato.........tomato......... dunno

Would have saved myself a bit of typing had I just thought to say that.
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« Reply #9 on: January 03, 2011, 09:27:21 pm »

Quote
Precious opal doesn't necessarily have to have fire.  Peruvian pink opal is an example.
i would disagree. Pink opal is semi-precious.  so is blue, and several types of potch with fire.  It really is about resale value, otherwise its opal. But there are allot of confusions even still into the twenty-first century.  Anyone... Bubble opal?
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