I thought that I should make a video on
Andamooka Matrix opal
[this] can this material can be treated and
Sometimes when you’re lucky, you’ll get results like this, so
trying to keep this short let’s
Let’s get into it. [I] started on this particular piece
Which is now about  ounces, but I started with 12 ounces [I’ve] cut pieces of it off
Andamooka Matrix opal is basically
opal [that] seeps into
Sedimentary rocks surrounding seams of solid opal in fact on this particular piece you can see this area is
Is a different shade and at the surface
This is a continuation of it. This is solid opal
You can see my finger through that this is solid opel with a mixture of
Opal adjacent to it
there was one large area on top of this on the top part of this stone that I thought that I could get a
Solid Matrix a solid opal
Cabochon and this is what I was able to get this is about 9 carats
so occasionally you get
you get areas in which the solid opel is adjacent to the
Matrix opal. Matrix means that the opal has seeped into the surrounding Matrix which is usually sedimentary rock like
Sandstone or Claystone siltstone mudstone
things of that that ilk I suppose that
[Claystone] or maybe the most common type
here’s an example of
a piece of treated Matrix this has been treated with
Placing it into a concentrated solution of sugar under heat
for a couple of days and then removing it and placing it in
concentrated sulfuric acid under heat for a day or so this is an area in which there’s a seam of
precious opal really nice quality precious opal within
an area of a Matrix opal of relatively low quality, but the
The precious opal is outstanding
This is what Matrix looks like
It generally is colorless, but you can get an idea of the of the color
Usually in some areas sometimes with lesser opal you can’t.
There is a type of Matrix opal that’s called Rainbow Matrix. Which is a very porous stone as lots of holes in it and
It it takes treatment very well, but is
Is more like pumice.
compared to say … I
Don’t know concrete or some
Rock like Sandstone or Claystone
I’m not talking about Matrix. I’m not talking about Rainbow Matrix. This is regular Matrix.
Now how is this going to treat? You buy a piece of Matrix opal and say, “Will this treat
well, or will it not treat well?” There’s no way really to know
Definitely the more solid it is the greater likelihood that
It will not treat.
To give you some examples:
Here’ is a large piece of Matrix. As you can see
the treatment is variable. Some areas didn’t treat at all
(This is polished specimen) Other areas treat extremely well
There really is not enough there. I just left it as a specimen. I polished it. It looks pretty good
Here’s another example that I expected the same results, but guess what?
That’s the only area that treated
the rest of it … these are
basically pebbles of a
different type of rock within it. But this is treated Matrix that didn’t treat so well.
This is one that treated a little better.
Here’s a little piece of
Matrix that’s been treated, but it’s nice-looking, but it didn’t treat so well.
Here is a little cabochon that I made out of
a lower grade of Matrix that treated fairly well, but it’s not very colorful
Here’s another piece very difficult to appreciate
If I can get this focused in … it is very
It’s pretty it treated very well,
But it doesn’t have a lot of color
now this particular stone that I dealt with a
[12-ounce] stone, I had to cut a lot away and I
Subjected the first thing I did is [that] I took some slices off
and removed the area of
mixed solid and Matrix and
I got that little solid
cabochon out of it.
But [I] wanted to test it as far as how well it would treat.
That would allow me to decide whether I wanted to
Parallel to the to the color bars
or whether I wanted to try to cut with the color bars — because I have a very nice color bar here and
there and it’s
Not quite as good there, but it’s it’s it’s enough. This is what I would call “Gem Matrix.” It’s got a lot of color
even when not treated.
So the first thing I did is I cut little pieces off. I sort of made little cabs [out] of it
Just to test the waters to see what?
Little pieces from around the thing would look like. And this is what I ended up with
That treated fairly well. It’s a little bit untreated there on one side of this rock on the side opposite the
part with the purple solid (opal)
was an area of true gem quality
Solid opal, but it was a very thin layer and on the backside of that, this is
What the matrix turned out to be. This is one side of the (main) piece.
Probably from a lot right there.
This this gave me real hope
Here’s another one. That’s a very nice
It’s very nice color
Here’s one that I polished completely
but it’s got that dividing line between the [bluish] in the more brilliant red and green because this one and
Somewhere in here. I have another little stone that came from this
This is a pretty impressive little
piece. So, with
treatment time I was able to see the potential. So then, I cut
full slice off of there and a full slice off of there, and I think a full slice off of there as well and
This is what they turned out to be this is a slice from here
And these two pieces are [from] this side
This broke in half
before I put it in acid.
So that’s the outer part the inner part you can see the variability in the treatment
This is actually a pretty impressive
thing with the white in it it almost looks like “Picture Jasper,” a type of
rock that shows a picture of a landscape, but that’s this side, and then this is an
87 carat slice
from the main side
This is the outer part with some dark spots and the inner
Honestly — about as good as it gets. The background is dark
nearly black with one one treatment and
We’ve got these incredible color bars, and this is cross-cutting although, it’s quite cut
perpendicular to the to the color bars
The other side has retained some
and it’s just getting into
The really great treatable Matrix on the other side. So, what I’m left with is, like I said, about …..
I think it’s 5.7 ounces of
untreated Matrix left and I
think that given the
Incredible color of this
(I’ll wet it a little bit..)
that I think I can continue to cut slices off of this and
and make outstanding cabochons that treat well and
And that’s my plan. So that’s a little lesson on
Andamooka matrix opal.
It doesn’t have the value of solid opal, but it sometimes has
the color of
the best of the best