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GeneralStrangest Minerals Faceted?

21st Jul 2019 16:38 UTCBarron Nguyen

Hey everyone! I recently came across a collection of faceted oddities, and a question came into my mind that I thought would make a good discussion. What is the strangest mineral that you have known to be faceted? This can be due to the difficulty of faceting, rarity, generally being too opaque to be cut, etc. For example, I know that even though sulfur is relatively common, it is very hard to cut, and thus is a strange mineral to be found cut. For clarification, the faceted material doesn't have to be a "gemstone", as there were past discussions on the definition of "gemstone". I would be thrilled to hear some stories and guesses!

21st Jul 2019 16:54 UTCJolyon Ralph Founder

I've seen faceted betafite which is pretty insane.

21st Jul 2019 16:57 UTCAlfredo Petrov Manager

There used to be a cutter in Bangkok, business name Freaking Cat, and the joke was he would facet anything. Would even facet a lump of asphalt from the highway, if you asked for it. Once in his booth I saw a faceted molybdenite. There is an expert cutter in Tokyo, business name Mithrill Tokyo, who even cuts water-soluble minerals like chalcanthite. It is said she can "cut anything except a crystal of monosodium glutamate from the chinese restaurant".

But apart from those oddities, I think the rarest cut "gemmy" materials are native sulphur, vivianite, realgar, and selenite, not because they‘re rare minerals - obviously they aren‘t - but just because they are extremely difficult to cut and polish, and only a small handful of expert cutters are able to do it.

21st Jul 2019 16:59 UTCKevin Hean

You may find this disgusting, but I have seen a human kidney stone cabochon ring.

Sometime back I faceted a bespoke Lapis Lazuli into an emerald cut which had to have a crack running across the table,

Looked pretty good actually, even if I say so myself :-)

21st Jul 2019 17:54 UTCBarron Nguyen

Betafite is an interesting mineral, of course, it would be best to have it relatively transparent, but wow, that would set off the counters. I have heard of Freaking Cat before and his radioactive faceting, but I wonder if he is still in business? Lapis Lazuli faceted, not something you see every day, but faceting "human pearls" is kind of horrifying, to say the least...

21st Jul 2019 18:13 UTCDon Saathoff Expert

Many years ago when I was doing research on the Barringer Mine now under Lake Buchanon in Burnet County, Texas I came across a newspaper article describing a pendant necklace with a large translucent green faceted gadolinite worn by a "wealthy local lady". I no longer have the article nor do I know the eventual disposition of the gemstone. It was rumored that the lady developed a tumor on her chest.....

Don S.

21st Jul 2019 20:26 UTCPeter Slootweg

At the 2019 St. Marie show a gem dealer had a flat of fulgurite cabochon's. That was something new for me. They were black glassy blobs, not attractive at all, but unusual to find them cut. The new find of Legrandite the year before also was available as cut stones.

21st Jul 2019 21:27 UTCFrank K. Mazdab Manager

Back when I was at the Stanford SHRIMP-RG lab, we bought one of Freaking Cat's faceted monazites as a potential trace element standard for monazite, a mineral of geochronological interest; however, I don't recall if that particular stone ultimately made the "cut". But as an aside, many of these faceted rare minerals, or their gem rough counterparts, can sometimes make quite good analytical standards, because the same factors that go into making a good faceted stone (being inclusion-free, being color zoning-free) often, although not inevitably, translate to the desired compositional homogeneity as well.

21st Jul 2019 22:17 UTCSteven Kuitems Expert

My most unusual faceted specimen is a faceted franklinite from Franklin, NJ.

21st Jul 2019 22:57 UTCRolf Luetcke Expert



Not that this is the strangest mineral faceted but one year at the Tucson show at the old Execuative Inn, one French dealer was selling these little sets that are 7x10 cm for the case for all of $15. I was not into faceted stones but for that price I picked one up. When I went back the next day to buy a few more, they had all sold out, no wonder.

I still have the display in my room cabinet.

Oddest one I had seen was a faceted wulfenite.

I think the Smithsonian or one of the major museums has a collection of faceted stones in every variety. That would be something to see.

22nd Jul 2019 00:03 UTCJolyon Ralph Founder

When I was in Madagascar I picked up a very nice faceted rhodizite

22nd Jul 2019 00:13 UTCA. Mathauser

Uraninite with fluorite (antozonite). Perfect for ring... not.

22nd Jul 2019 02:06 UTCTony Albini

I have seen facetted pollucite from Connecticut and Maine material. Not bad for a zeolite mineral.

22nd Jul 2019 02:13 UTCRudy Bolona Expert

I saw a faceted behierite on Ebay sometime ago.

22nd Jul 2019 02:24 UTCRoger Ericksen

After there was a find of large Natrolites in Bound Brook NJ in 1960's, some large broken xl sections were faceted. Not as rare but a Zeolite.

22nd Jul 2019 13:26 UTCBarron Nguyen

As a side discussion, what would you consider to be the rarest mineral faceted?

22nd Jul 2019 13:49 UTCAlfredo Petrov Manager

If you had asked that question a few years ago, Barron, people would have answered painite, or perhaps taaffeite (now "magnesiotaaffeite-2N‘2S"), although recently the number of known stones has considerably increased. The current rarity record holder is probably kyawthuite - https://www.mindat.org/min-46909.html - known only from one or two cut stones and no collector has a piece of the rough uncut mineral, although I would be delighted to be proven wrong if someone has a piece to show us.

22nd Jul 2019 14:45 UTCKevin Conroy Manager

Alfredo, out of curiosity, is there a bug regarding the kyawthuite photo? It doesn't register in the photos on the mineral page, and doesn't appear on the locality page: https://www.mindat.org/loc-243334.html

22nd Jul 2019 14:53 UTCKyle Bayliff

That is a weird one, even if it weren't faceted. I wasn't aware there was a mineral with antimony in the 5+ oxidation state. Chemically, the only other place I can think of seeing Sb5+ commonly is the antimonials they use to treat leishmaniasis (and that's some nasty stuff).

22nd Jul 2019 15:26 UTCBarron Nguyen

Alfredo, funny it's another rare mineral from Mogok as there are already a bunch more, such as the old previous record-holders.

22nd Jul 2019 15:42 UTCTony Albini

Spodumene, variety hiddenite, has been faceted from material from the Adams Farm, Hiddenite, North Carolina. Much rarer than the other varieties of spodumene, which form large gem crystals.

22nd Jul 2019 16:00 UTCAlfredo Petrov Manager

Kevin, I‘m not sure why the kyawthuite photo does not appear on the locality page. I do see it on the species page (the one I linked to in my post above).

22nd Jul 2019 16:14 UTCBarron Nguyen

I have heard about chambersite being a rare mineral found as a faceted due to some gemmy crystals found.

22nd Jul 2019 17:08 UTCSusan Robinson

I've seen faceted stones of halite, cuprite, and from Mt. St.-Hilaire, Quebec, transparent wollastonite and villiaumite.

22nd Jul 2019 17:21 UTCDavid Von Bargen Manager

"Kevin, I‘m not sure why the kyawthuite photo does not appear on the locality page." -it was marked user only.

22nd Jul 2019 18:54 UTCKevin Conroy Manager

David, thanks! I didn't even think to look for that.

22nd Jul 2019 19:06 UTCFrank K. Mazdab Manager

Hi Kyle,

there are actually a number of Sb5+ minerals, from several different geologic environments, and from a variety of different chemical families. If you do a "search by chemistry" for Sb and O, you'll see them along with with their Sb3+ brethren.

22nd Jul 2019 19:44 UTCRolf Luetcke Expert

One fellow I met at the Sierra Vista Arizona small mineral show was talking to a dealer friend and he was showing the dealer a small reiker mount of more than a dozen wonderfully colorful faceted pieces and he said they were all different colors of glass and I was amazed at the luster he got from just glass. Again, not a rare mineral but just thought it was something I had not seen a man specialize in.

23rd Jul 2019 15:20 UTCLászló Horváth Manager

From Mont St-Hilaire: villiaumite (water soluble), shortite, leifite, catapleiite, carletonite, serandite, rémondite-(Ce), narsarsukite have been cut.

24th Jul 2019 07:35 UTCHarald Schillhammer Expert

Jolyon & Katya Ralph Wrote:


> I've seen faceted betafite which is pretty insane.

What about Thorite and Ekanite from Myanmar ;)

24th Jul 2019 08:16 UTCErik Vercammen Expert

At the Tucson show a lot of years ago, there was faceted talcum, the softest of all minerals.

24th Jul 2019 08:30 UTCAlfredo Petrov Manager

As a friend pointed out - faceted frozen grape jelly. I‘m sure it was beautiful, if not exactly wearable, except perhaps in Siberia in February.

24th Jul 2019 08:32 UTCHarald Schillhammer Expert

Alfredo Petrov Wrote:


> As a friend pointed out - faceted frozen grape

> jelly. I‘m sure it was beautiful, if not exactly

> wearable, except perhaps in Siberia in February.


24th Jul 2019 15:11 UTCBarron Nguyen

Faceted grapes? What about faceted ice?

24th Jul 2019 17:23 UTCLuca Baralis Expert

Alfredo Petrov Scritto:


> ... kyawthuite -

> https://www.mindat.org/min-46909.html - known only

> from one or two cut stones and no collector has a

> piece of the rough uncut mineral ...

Yup? No rough type specimen?

24th Jul 2019 17:40 UTCAlfredo Petrov Manager

Right, Luca. I think the type specimen is the cut gem.

24th Jul 2019 17:49 UTCDavid Von Bargen Manager

The original crystal of kyawthuite was a waterworn,

roughly rectangular prism weighing 3.66 carats.

There were no images taken or other measurements

made of the original crystal. The gem faceted from

the crystal is a rectangular cushion weighing

1.61 carats and measuring 5.80 mm × 4.58 mm ×

3.00 mm (Fig. 1). No fragments were saved from

the cutting process; however, several small fragments were successfully removed from the culet of

the gem without compromising its general appearance. These were used for the ensuing description,

whereas the entire stone was used for the density

determination and infrared spectroscopy.


24th Jul 2019 19:53 UTCFrank K. Mazdab Manager

wasn't the original near end-member pale blue magnesio-axinite from "East Africa" also first described from only a single cut gem, and it was only years later that the source was discovered as the tanzanite mines around Merelani; now anyone can own a piece. Perhaps there's hope for rare mineral collectors, and rare mineral facetors, that kyawthuite will follow a similar trajectory.

24th Jul 2019 21:05 UTCKevin Conroy Manager

Barron Nguyen Wrote:


> Faceted grapes? What about faceted ice?

I had a rectangular-shaped faceted ice, but last night it melted in my tea.

25th Jul 2019 02:12 UTCEd Clopton Expert

The Harvard Mineral Museum has a 30 ct. gemmy faceted willemite from Franklin, N.J. It probably even fluoresces.

25th Jul 2019 17:13 UTCBarron Nguyen

The good thing about ice is that it self-polishes too!

29th Jul 2019 20:00 UTCMatt Ciranni

There is a website, classicgems.net, which has all kinds of strange oddities as far as faceted stones. Stuff which I have never heard of, (e.g. inyolite, Magnesiotaaffite, musgravite) Stuff that I have heard of but which is pretty rare (e.g. jeremejevite, pezzotaite) and all kinds of radioactive weird stuff like Samarskite, thorite, and betafite- "Gems" which you certainly wouldn't want to wear as jewelry!

22nd Oct 2019 23:03 UTCNicolas Christol

Hello everyone! I have a collection of rare gems, not biggest or best ever but I have some super rarities like Kämmerérite or Boleite or bicolor Anatase, and a Veszelyite coming soon ;) www.christol.ch
Years ago I had a betafite rough, I was starting art school and had made an installation with the stone and a photograph, anyway a visitor had stolen the stone... I fetl quite sorry for him/her

23rd Oct 2019 19:42 UTCMatt Ciranni

I wonder if, by some odd coincidence there were any thieves checking into a local hospital next to your art school complaining of sores, hair loss, unexplained fatigue, and thyroid cancer?
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