What Color is black Opal?

black-opal-red on black opals loose

red on black opals loose

A pretty simple question you would say. Requiring an obvious answer, ‘BLACK OPAL IS OBVIOUSLY BLACK’  Well if you said that, you would be wrong. Such a confusing answer begs a good explanation and we intend to give it to you in this article.

First though, let’s take a look at some of the history of opal.  Opal has been around for a long time. Probably a long time before diamonds, at least in the current structure or shape.  Diamonds, for example were not very pretty stones in their original context because in old times they didn’t know how to cut and polish them because they were too hard to handle.  It wasn’t until around the 15th century that they eventually started to get some shape to them.  More on this subject here.

The History of White and Black Opal

Light or white based opal history stretches back to the days of the Romans.  But this article indicates that they could stretch back thousands of years B.C. As far as we can tell all these historic opals were white or light based opals, not black opal.  That means that the brilliant opal color in the foreground, sat in a white background.  Sometimes this white opal background was on the surface and was opaque (not able to be seen into) Whereas other opals were more translucent in that you could see deep inside the stone, some stones even bordering on being see-through, with just a glimmer of opal color responding to light.

The discovery of Black Opal

 The opals shown above are examples of the black potch left in the background of black opals. The opal with the black, red, green, pink stripes is a good example of how the black potch is found along with the bright crystal opal. As is seen in the parcel of small crystal and black opal, the color bounces back at you and has a more striking contrast when the black potch is left in the background of the opal color.  Without that black opal potch, the resultant stone would be crystal or pale opal, not black opal. See ‘natural opal types”

As far as we can tell, it was not until the twentieth century that Black Opal was discovered in Australia. (This is by no means meant as an absolute statement because I have seen examples of very dark, nearly black opal in Indonesia but I doubt they were known historically) Boulder opal which has a brown ironstone backing was the first discovery and Boulder opal according to the latest nomenclature, is now considered one of the varieties of black opal.  Black opal was discovered mainly in Lightning Ridge, Western NSW, Australia.  Here is the history

So Then if it’s Not Black, Why Do they Call it Black Opal??

The reason is that, unlike white or crystal opal which has a pale background, Black opal is found in the ground associated with a black material called black potch, instead of white potch.  Just why the opal potch in Lightning Ridge is black is open to conjecture, but that’s the way it is.  So, when the opal cutter processes the stone, he cuts it so that the brilliant black opal color is in the foreground, and the colorless black potch is in the background.  The effect of this is to throw the color forward, giving opal that dynamic brilliant effect that just tantalizes you.

So, when black opals were first discovered, the first reaction was to view them as a contrast to the white opals and whether rightly or wrongly, the name came up Black opals.  Hence from that time onward people have thought that black opals are black when in actual fact they can be any color of the rainbow.  The black opal part of them is just in the background.

Here are some examples of black opal cut and polished but unset.  And others which are a mixture of boulder opals, doublet opals, and black opals, that have been set into gold and silver jewelry.

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