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GeneralIndonesian purple chalcedony

8th Jun 2016 10:57 BSTPeter Slootweg

Lately i have seen a lot of specimens from Indonesia in the form of clusters composed of small spheres claiming to be chalcedony. I come's in purple, green, white and black hue's. I find it suspicious but beautiful material and there seems to be al lot of it. It is sold on the internet as grape agate/chalcedony. My question is if anybody can confirm this as natural, as all the specimens i have seen to date are without any matrix.


8th Jun 2016 11:27 BSTKeith Compton Manager

Hi Peter

They certainly look real to me, or at least the two that I have viewed up close.

Very nice under a scope too.

The "nodules" average around 1-4 mm in size. I would consider them too small to be artificially produced or carved like those Chinese "grapes" which are either quartz or fluorite and rounded with some form of sphere machine - basically all half spheres ground out of a solid mass. Many look very good admittedly but most have crude polishing around the base and they are obviously fake.

These from Indonesia look totally different.

Whether they are chalcedony or whether they could be called Amethyst - I am not sure but I think Chalcedony is correct

It would be good to have them analysed to ensure that they are not another mineral altogether. As more are appearing, I'm sure someone will do a definitive test. I see that some are described as Suiseki Chalcedony (those who grow Bonsai will be familiar with the term).

They are very nice.

I would certainly like to see more literature on the location.



8th Jun 2016 13:35 BSTDavid Von Bargen Manager

I saw one recently at a show and it was over a foot in size. These are definitely not carved. Most of the material is fibrous (radiating balls - therefore chalcedony), but there are some areas that have extremely small crystals growing on the surface so probably could be called amethyst.

8th Jun 2016 13:56 BSTAlfredo Petrov Manager

I have the same observations as David. A few of the tiny crystals were twisted.... micro amethyst gwindels? :-S

And I wonder whether chalcedony can be colored by the same mechanism that colors amethyst? And then what would we call it?

Some parts of the deposit yield green balls rather than violet ones. Haven't had a chance to look at it under high power yet, so idk whether the green is intrinsic to the silica or due to an admixed substance like celadonite.

Some sellers at the Tokyo show had it labelled as being from Sulawesi, but none had visited the deposit. Eventually an exact locality will be found out, as usual, I suppose. Patience.....

8th Jun 2016 15:07 BSTAmir C. Akhavan Manager

Quartzine (length-slow chalcedony) can grade into macrocrystalline quartz in botryoidal aggregates, as it does in amethyst specimen from Nyíri

The same probably happens here, too.

I could not think of anything that would generally preclude chalcedony (length-fast or lenght-slow) from possessing amethyst color centers. Of course, too many impurities could destabilize color centers and prevent their formation.

I think I've seen similar specimens from another locality, but can't remember from where.

You can heat a small piece to 300-350deg C and see what happens to the color. If you are very patient (several months), try to bleach one in the sun or UV.

8th Jun 2016 15:46 BSTRiccardo Modanesi

Hi to everybody!

What you call "chalcedony" is truly amethyst. Amir is right: in Hungary some good specimens of this quartz, crystalized this way, are found. Therefore I fully agree with Alfredo. I think the specimen represented in the photo is real and natural.

Greetings from Italy by Riccardo.

8th Jun 2016 21:48 BSTŁukasz Kruszewski Expert

Beautiful, nevertheless (tu)

9th Jun 2016 10:48 BSTPeter Slootweg

Thanks for the comments guys!:-)

9th Jun 2016 19:16 BSTTravis Hetsler

I have seen it called "Manakarra grape agate" and have a nice 4kg piece in my collection, purchased in Tuscon. Under magnification I see no signs of tool marks, etc indicating a man made carving. When broken open I see a radial structure, a nucleus, and the color is even throughout each orb with the nucleus just a tad darker than the rest.

11th Jun 2016 15:34 BSTAlfred L. Ostrander

If it is chalcedony, why shouldn't it be called purple chalcedony? That does avoid one more varietal name.

11th Jun 2016 16:48 BSTTravis Hetsler

There is also an "Indonesian Purple Chalcedony" or alternatively "West Java Purple Chalcedony", that forms deep purple veins as opposed to orbs, so I am sure the name "Agate" was used as a trade name to avoid confusing the two (which seems to have had the opposite effect lol). See link:

17th Jan 2017 01:01 GMTKEITH (Keith {Not Given})

I have recently acquired a kilo of small pieces of this material and after a thorough inspection I found several pieces that had little clear crystals on top of some of the spheres that when i examined with a jewelers loupe of 10x look like a perfect stilbite and some were clearly six sided quartz crystals with multiple termination on both ends. I know this is relatively new material and am still looking to see who has done some further mineralogical study on this material.

17th Jan 2017 02:42 GMTAlfredo Petrov Manager

Analyzed some interstitial waxy material yesterday from a still uncleaned botryoidal violet chalcedony. It was saponite.

7th Mar 2017 14:40 GMTTim Jokela Jr

Would you call this material amethyst, Alfredo?

For anybody wondering, it is indeed natural, not carved, dyed, or anything.

Found as individual spheres to large clusters, floaters, no matrix, in clay.

7th Mar 2017 15:02 GMTWayne Corwin

Love to see some of those in situ :-D

10th Mar 2017 16:42 GMTTravis Hetsler

The article posted below that gives the most detail I have seen as well as mining shots of this chalcedony.

10th Mar 2017 18:41 GMTUwe Kolitsch Manager

Thanks, added to locality page.

10th Mar 2017 18:56 GMTJolyon Ralph Founder

Note that some pieces of this are dyed to enhance the colour. But there are also plenty which are natural.

24th Mar 2017 12:11 GMTChristopher Jolicoeur

I have a fair amount of this... about 5 kilos. Large pieces and small. I discussed it with my mentor the other day who also has a piece and he said it is a purple form of Melanophlogite. What colors it purple he was not sure. What are your opinions on this? Perhaps this topic should be moved from the fakes and frauds as it is no longer being discussed as that?

PS I am new... nice to meet you all! -Chris

24th Mar 2017 15:00 GMTUwe Kolitsch Manager

"I discussed it with my mentor the other day who also has a piece and he said it is a purple form of Melanophlogite."

I would choose a different mentor.

24th Mar 2017 15:10 GMTChristopher Jolicoeur

ok.... thank you for your thoughtful advice. So the common consensus among experts is that it is in fact a botroydial purple chalcedony? I'm trying to nail this down so that when I sell it I am giving proper information. Thank you. -Chris

24th Mar 2017 16:35 GMTAlfredo Petrov Manager

Christopher, the crystal habits in the material are quite variable; some is cryptocrystalline chalcedony, others are botryoidal masses of small terminated amethyst crystals which are not chalcedonic.

24th Mar 2017 16:53 GMTChristopher Jolicoeur

Thank you Alfredo for that specific information. I do appreciate knowing exactly what it is. Such an interesting material. I believe my mentor shall get demoted for his false claim.

24th Mar 2017 19:25 GMTJolyon Ralph Founder

The names 'grape agate' and 'grape chalcedony' have been used for this material on the market, and these are simply trade names.

There are many other 'trade names' that don't accurately represent the mineral species described'

'Bohemian Topaz'

'Herkimer Diamond'

'Moss Agate'

etc etc etc

It's not up to us to create a new scientifically accurate name for this material. We have one already, and it's this.

For trade names, we simply report what names are being used and what the material really is.


6th Apr 2017 01:17 BSTJason Evans

Keith, I too have found those transparent sheaf like crystals in my purple Indonesian chalcedony/botryoidal amethyst and my first thought was stilbite, but looking closer it does not seem right for stilbite, they are more like dumbell or peanut shaped , not like the wheat sheaf form of stilbite. then I looked at some of the photo's that have been uploaded and saw that rice grain and sheaf like crystals are found with this, mine has boith of those forms, and it says it is quartz. I find this really intriguing as I never knew quartz could grow this way, then again I also never knew that quartz could form as botryoidal aggregates of small terminated crystals!

I got this specimen simply because I thought it looked nice, and it's turned into something far more interesting than I expected!

Are there any links to photos of quartz showing this habit?

6th Apr 2017 04:26 BSTClifford Trebilcock

Keith and Jason,

I have also noted these tiny dumbbell shaped crystal forms in a batch of small groups of purple chalcedony balls.

To me the they appear to be made up of tiny quartz crystals. Also noted individual regular shaped quartz crystals

on occasion attached to some spheres. The dumbbell shaped forms remind me of many of the artichoke quartz

crystals from the Francon Quarry in Montreal.Interesting specimens under the scope.


6th Apr 2017 17:28 BSTScott Rider

Those little sheafs almost look like two spheres molded together. I have a few pieces of this material and none have that, but under 40x loop the other spheres do seem to be made up of tiny pyramidal terminations!!!

One of my specimens color range goes from a pasty white, to green to some orange, and finally purple. The white aggregates almost appear to be included by a clay like mineral. And the orange almost appears like iron-oxides... So maybe there is a lot more involved on at this location than we speculate.

The one thing I did notice is that the chalcedony specimens from some parts of Maharashtra, India are very similar. Not the color, as they are usually colorless, but the crystal forms are quite similar. I have a few pieces from there that have pretty much the exact same crystallization from India. Little spheres that appear to be made up of tiny terminated quartz crystals. Cross sections reveal that there could be at least 2 generations, a fiberous acicular formation of chalcedony making up the majority of the sphere, topped off by a 2nd gen, macroscopic "regular" quartz terminations. It is just like the Indonesian material.

Either way, I love these specimens. If you get a good one, they sparkle with a purple glow that is truly unique!!!

6th Apr 2017 20:52 BSTAlfredo Petrov Manager

This discussion should not be under the "Fakes and Frauds" messageboard! It could give the wrong impression to beginners.

7th Apr 2017 01:06 BSTDoug Daniels

Remember, in the original post the question was whether such specimens were natural or fake, which is likely why it was posted under "Fakes and Frauds". Maybe it should have been posted in the general messageboard first, but, I can understand why it was done as it was.

7th Apr 2017 01:36 BSTPeter K. Szarka

Alfredo's partly correct. This topic should not be in this thread if questioning the legitimacy of the specimens. They are real and have been available for some time now in various colours: yellow, brown, green, gray, purple. Some specimens have gradients of colors across them. Not uncommon to see green, grey and purple together.

I've watched the evolution of this stuff's availability on eBay from the start. These first started appearing commonly from Indonesian sellers on eBay well over a year ago, closer to two. Then YouTube videos started showing up with Indonesians selling the material. Chinese sellers next appeared with them next a few months later. Price went up, size came down on cherry-picked specimens. Finally, a few Americans started listing these in the Fall of 2016. Now there's a flood of this material everywhere.

And here is where I'd consider this topic eligible for inclusion in this thread as a marketing ploy. In person, the vast majority of these specimens look much the same as many other chalcedony dug out of clay. Dull, earthy, with no sparkle. But with the huge influx of grape chalcedony/grape agate occurring early summer 2016, sellers' specimens started taking on great lusters. I suspect oil, silicone, leafshine, water, etc. is being used to 'enhance' them. Not exactly a new ploy in the mineral business. And this is as far as the deception goes I think. The actual specimens are real. But you'll have to watch for 'enhancement'. A soapy water wash of a glistening piece might disappoint a buyer.

7th Apr 2017 01:52 BSTPeter Slootweg

-- moved topic --

23rd Apr 2017 17:18 BSTcascaillou

check this link for a list of chalcedony treatments:,62,369000,369000

25th Apr 2017 04:24 BSTMarek Chorazewicz

George Rossman had mentioned finding some phillipsite in the volcanic matrix on the back side of his purple grape specimen from Indonesia when we talked at the most recent MSSC meeting in Pasadena...

Best Regards,


25th Apr 2017 11:11 BSTJoel Dyer

Peter, this has turned into such a lengthy thread that I hope I haven't missed something...

Have you got any of the spherules analyse? XRD might be able to tell you the crystallization degree of the material.

Raman spectroscopy will tell you even better what SiO2 phase this is, partiularly if it contains for example moganite.

I'm in the process myself of starting - or actually continuing - a joint publication project with an experienced mineralogist, concerning moganite & quartz content in Finnish vs foreign chalcedony & some other similar SiO2 materials.

Of course, there have been similar studies carried out already, but no such comparitive work in Finland yet, as far as I'm aware and have been told. Please correct me if this is not true.

So, if you would like me to include some of your material in the study, I'd do it for nothing, but would need a few "balls" of the stuff, preferably slightly different looking / different shades. The same goes for other chalcedony/flint/agate etc chip donations. You will be provided with the anaysis results, no charge. This is a one-off project deal for me, for a limited time only ;-) .

You (whoever it is) can get hold of me via a private message or preferably via firstnamelastname"at"



26th Apr 2017 00:13 BSTPeter K. Szarka


Thanks for that link. I was not aware of it and it's highly informative. The scope of treatments is truly astonishing.

20th Jul 2017 10:52 BSTMacro Cosmos

I recently acquired a sample and took a photo at high magnification:

Tiny cubical formations essentially form the botryoidal structure, really interesting. They are truly amazing!

17th Aug 2017 14:58 BSTTim Jokela Jr

Huh? What "cubical formations??

The sparkly material is sparkly because of countless minute quartz crystal terminations.

Interestingly, one piece can have both sparkly and smooth spheres, as well as green and purple.

Fantastic stuff under the scope, photomicrographers need to get busy!

17th Aug 2017 15:18 BSTTim Jokela Jr

Still can't quite wrap my head around what to call this stuff.

The spheres are fibrous in cross section, but surfaces can be composed of crystal terminations, and both sharp single micro crystals and clusters can be scattered upon the spheres, or even make up a matrix for the spheres.

Specimens can be composed of both sparkling exterior crystalline, or smooth, non-crystalline spheres, side by side.

Is it truly cryptocrystalline chalcedony, or crystalline amethyst???

Upon what specific evidence was the term chalcedony chosen by MinDat?

17th Aug 2017 18:17 BSTAlfredo Petrov Manager

I don't think a single name suffices, as the material is so variable. Some is botryoidal amethyst, others look like chalcedony or transitional varieties between the two, and the chalcedony can be violet, green, pale grey.... No one name could fit all of them.

18th Aug 2017 02:31 BSTDoug Daniels

What the heck, let's make up a new name - chalcemethyst. Really confuse people. (OK, just being a jack-o-lantern.....)

18th Aug 2017 11:27 BSTReiner Mielke Expert

You could cover all the possibilities by simply calling it "grape" quartz.

27th Sep 2017 19:15 BSTaco farid

I have a botryoidal variant from Indonesia but I don't know the type

27th Sep 2017 19:16 BSTaco farid

what is this

10th Oct 2017 07:40 BSTJoel Dyer

I would tend to agree with the comments that the structure of this type of material must vary a fair bit, but would personally call the material (grape) quartz rather than (grape) chalcedony / agate.

I received just recently from Tim Jokela 3 different looking samples: darker purplish, lighter purplish and green. All of the samples show clear crystallinity, with varying sharpness of light refraction.

The lighter purplish material showed clear signs of moganite (10-15%), the other samples just quartz peaks, compared to reference macroscopic quartz crystals.

The light purplish material also showed 2 kinds of crystal habit, sharper terminated elongated crystals in sheath-like formations, and almost pseudocubic form aggregates, quite interesting.

The FOV's here are 0.8mm. Both reflected and transmitted plane-polarised light was used, thus the colour reproduction is not quite true.


11th Oct 2017 10:27 BSTOlav Revheim Manager


It would be really nice if you upload a picture of the full size specimen with these photos as child photos to this locality

I think these photos are really educational and interesting


12th Oct 2017 08:22 BSTJoel Dyer

Hi Olav, thanks for your message.

Do you mean I would add as the main photo the full-specimen picture, then the above two as child photos, perhaps along with 1-2 Raman analytical data child photos?



12th Oct 2017 12:47 BSTOlav Revheim Manager

Hi Joel,

That would be perfect!



12th Oct 2017 22:26 BSTJohn Oostenryk


Oh Please DO!

I find this material very interesting- and your imagery would be a great aid to conveying/explaining the current description!

For a humorous aside~(and nothing else!) The appearance of the crystalline surface- immediately brings to mind a common formation in the "Keokuk geode region" sedimentary geodes.

A thin layer of chalcedony overgrowth of the quartz crystals. These are like an inside-out one... in MICRO scale :)-

Best Regards!


Assistant Curator,

Fryxell Geology Museum

12th Oct 2017 22:47 BSTOwen Lewis

I've been following the recent posts here with interest. I would agree that *some* does not look like chalcedony. Is it possible that some occurrences are quartz and some are chalcedony?. Both amethystine quartz and amethystine chaldedony are reliably identifiable by simple testing and basic gemmo tools.That'd my my start point for further enquiry anyway.

If one of you guys that have some break off a a piece or two of the partly transparent spheroids (likely quartz), You can test for:

- Fracture lustre.

- Optic character

Get a piece polished optically flat. and you can get the (different) RIs for both quartz or chalcedony specimens and sort them out with confidence. I would not want to rely on hardness and SG testing in this instance.

13th Oct 2017 03:24 BSTAlfredo Petrov Manager

The purple material loses colour on heating in a test tube in a gas flame, which makes me think the colour is most likely due to irradiation damage, as in amethyst, so the name "amethystine ..." would be appropriate.

13th Oct 2017 13:09 BSTOwen Lewis

Good thinking Batman!
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