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Blue Quartz/Blue Agate

Hi everyone, I have a question about a stone I have been finding all
over the place as Blue Quartz. At one source the same stone is
called Blue Agate, but this is the only place I’ve found calling it
an agate. It is an opaque stone, the color of a dark blue summer
sky. Does anyone know which, if either, of these materials the stone
actually is?

Carrie Otterson

Most likely it is dyed.

There are several blue agates and blue chalcedonys, they can be very
beautiful; they usually will be translucent on an edge, similar to
the translucency of chrysochrase.

It may also be “succor creek” or “swamp bog” picture agates, which
are actually jaspers (they are opaque); however these materials are
not in wide commercial use, as they are uncommon.

So, if the material looks a little too uniform, it may well be a
dyed or synthetic.

It most likely is not quartz.

Mark Zirinsky, Denver
’private cutter buying rough and materials’

Carrie, Is there anyway that you can send a photo of this material to
me offline? I have cut a lot of blue agate in the past as well as
blue quartz. The lighter sky blue material tends to be either agate
or chalcedony while blue quartz tends to be more of a washed denim
color. Thanks

custom cut designer cabs/concave facetted gems

Hi Carrie, The only stone I know as blue agate is blue lace agate,
and (as I’m sure you know) that’s a baby blue with white striping.
I have some blue calcite that is dark blue, pretty opaque…let me
know if you want me to scan it and send a pic to you. If your blue
quartz is translucent and faceted, it may be some of the “fruit
quartz” (blueberry quartz, pineapple quartz, and so on) that seems
to be everywhere…but the consensus is that it’s really glass.
Hope that helps some!

Carrie, These days, with the proliferation of fake (glass) or
color-treated gemstones (beads especially), it’s easy to get duped.
Gerry Galarneau of Galarneau Gems recently recommended to me that
when buying, keep close a copy of a good gem reference book. I have
June Culp Zeitner’s Gem and Lapidary Materials (1996 is latest
edition that I know of) – what are other favorites, all?

Anyway, June says of blue quartz that it is fairly uncommon (in gem
grade) and found in southern US states; colors range from faint
grayish or whitish blue to smoky, sky, and medium gray-blue.

Since this stuff is all over the place I guess I might wonder…If
your merchant can’t provide decent provinence I’d be suspicious;
there’s also an easy way to tell if it’s glass – look at it under a
simple pocket loupe and if there are bubbles, it is glass. I did a
Google of “blue quartz” and found a lot of honest dealers selling
beads as “blue quartz - synthetic”.


It’s probably cryptocrystalline quartz, agate is a variety. These
materials are commonly dyed. Agate = quartz. A great reference is
"Gem Cutting" by John Sinkankas; it should be in everyones library
who’s interested in stones and lapidary.

Hi Carrie, Agate, a type of chalcedony, is a member of the quartz
family (chemically, silicon dioxide). The difference is that all the
varieties of chalcedony (agate, jasper, etc.) are microcrystalline or
cryptocrystalline. In other words, they are composed of microscopic
crystals of silicon dioxide as opposed to what we call quartz, whose
well-formed, definitely non-microscopic crystals we’re all familiar

Agate is distinguished by its banded appearance and usually includes
translucent material; jasper is massive, dense and opaque.
Microcrystalline quartz which is translucent but not necessarily
banded is called simply chalcedony (like the recently very popular
blue chalcedony).

Assuming the material you’ve described is actually natural quartz
(as opposed to a simulant, like glass) and if it is even slightly
translucent rather than opaque (which I suspect), I would be tempted
to call it chalcedony. It’s difficult to nail down without seeing
the rough material it came from.

On the other hand, if in the rough it formed a band between other
colors of quartz minerals, then it might properly be called agate.
Either way, you can’t really go wrong calling it quartz which is the
umbrella term for the whole family of minerals.

I’ve not seen this material, by the way, but I am not aware of the
availability of large quantities of a dark blue quartz. My guess is
that it’s dyed or otherwise color-enhanced.


There is a stone that comes out of Washington that is a deep blue
quartz. From the consistancy, I would call it a quartzite and not a
chalcedony. Some of it has white stripes. It is beautiful as an
ocean in intarsias. Rose Alene McArthur

Keep in mind that there have been quite a few deposits of Blue
Chalcedony or for us commoners AGATE, one very large deposit in
Malawi or something like that in Africa, and then there is the
Ellensburg deposit, and one in the Mojave Desert But these are not a
bright vivid blue they are more of a very light very pale gray blue
with the Ellensburg and the Mojave deposits producing the better
colors. Blue Chalcedony was quite popular two or three years ago the
better colored material was bringing several dollars a carat. I just
got through cutting some of the African material and it’s just your
typical micro or crypto crystalline silicon in other words it’s just
an agate. If your material is a very bright blue it is probably just
dyed agate Excuse me I meant Chalcedony I forgot where I was I
used a lot of it until I found out how quickly it lost its color when
exposed to sunlight, Oddly enough the green dyed material doesn’t
loose it’s color very easy nor does what is sold as black onyx which
is still just dyed agate, but the green and black seem to be quite
permanent colorings,

Kenneth Ferrell

I’d be interested to know what people think this stuff being sold as
multi-blue quartz really is. Here is a link to the page that it is
being sold at :

Thanks, Nicola.

Nicola -

The beads at that link appear most like glass, although I expect they
could be some form of quartzite, like what is most often called
dumortierite. Chemically-stained, well-cemented quartzite will cut
really nice stones, so we can hope for this to be the case. The
material is almost definitely not agate, nor crystalline quartz,
based on the appearance of the beads.

Jim Small
Small Wonders Lapidary

Hello Beth, Your erudite discussion about chalcedony brought up a
question for me. I hope someone can answer this:

Is the beautiful aqua-colored chalcedony I saw at Tucson (and now in
some advertisements) color treated? The color is so uniform that
I’m assuming it is not natural, but this inquiring mind would like
to know.

Thanks in advance, Judy in Kansas were - would you believe it!- there
are flood warnings out for some areas. We are grateful for the rain

Judy M. Willingham, R.S.
B.A.E. 237 Seaton Hall
Kansas State University
Manhatttan KS 66506
(785) 532-2936 FAX (785) 532-6944

A bead dealer who has been very friendly with us and always shares
info said that the material is a rare type of obsidian from China, he
talked about having the material tested, (by GIA I believe?) and they
were unable to name it but said it was a natural material, not man
made. I think his strands were around $25.00. The beads had a
chatoyance similar to fiber optic glass and I found it hard not to be
skeptical. Mark


Having hunted extensively for blue calchadoney AKA ELLENSBURG BLUE,
I have found that true blue coloration by iron ion4 will have a
yellow to pinkish glow in the finished piece. I have found the
extremes to be carnelian on one end and almost purple on the other.
the way to tell if they are true is to look for growth lines or in
the case of pure gel deposit clarity that will carry the glow. Blue
quartz on the other hand can be colored by other minerals that do
not carry the glow but almost always show lines of growth. I have
found deposit and pieces that carry that effect throughout the state
Of Washington.


Hi Judy,

Is the beautiful aqua-colored chalcedony I saw at Tucson (and now
in some advertisements) color treated? 

If you mean the “Sea Blue” chalcedony sold by Maxam Magnata and the
similar material sold by many others, the answer is yes. I can’t
remember if it’s dyed or something else, but it is definitely
color-enhanced. Beth

No disrespect meant, but I find it hard to believe that GIA couldn’t
i.d. obsidian, a volcanic glass. Did you send it to GIA? Unless
you are speaking from personal experience it should be noted that it
is not first hand experience.

I have a friend who travels to China and returned with several kilos
(maybe 100?) of a blue material. The dealer in China didn’t know, or
wouldn’t tell him, what I was. He had me look it over and cut some of
it for him. With that amount to look at there was no question, it was
man made. It looked like someone was trying to make Victoria Stone
(and failing). The material was harder than normal glass but cut
like glass. Some of the material was bubble free but bubbles were
plentiful and some areas were actually frothy. It did not have a
conchoidal fracture, I did not do a SG test on it. There may be other
blue material coming out of China but I don’t think the material I
saw was looked at by GIA, they would not have mistaken it for

Dick Friesen

    I used a lot of it until I found out how quickly it lost its
color when exposed to sunlight,  . . . 

Hi Kenneth. Do I understand correctly that you are referring here to
the dyed blue chalcedony rather than the natural Namibian material?
Thanks. Pam

Hi Kevin I think the bead dealer said that the person who brought the
material over and had beads cut was the one who had it tested, and I
think he said the testing was done by GIA. The stuff looks like glass
to me too though, and I find it hard to believe GIA wouldn’t be able
to spot that, probably just a “story”.


Yes I was referring to the dyed Agate, Then Namibia blue mist or
what ever they are going to call it this week is a Natural material
and as far as I know holds what little color it has, To me it looks
like a singular replacement and not a fortification type of agate
that the Blue Lace agate is but most I have cut has been about the
color of the pale blue grays that blue lace has. I have some material
that has recently come out of China, it was advertised as Blue
Moonstone, how ever it exhibits no similarity to any Feldspars I have
ever seen, has no ardulesence, and seems prone to conchoidal
fracturing, I haven’t looked at it under any high power magnification
but to me this material more closely resembles Obsidian or glass. Ahs
any one else seen or heard of this “rare new material”

Kenneth Ferrell