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Setting emerald cut gem quality rhodochrosite

I have a client who would like me to design and set her 3.01ct. 9.6x6.9mm Gem Quality rhodochrosite…for a RING!!!
I’m nervous. Any suggestions, any experiences?
Thanks so much for your suggestions!
Lucine

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Four _Hands welcome,

Rhodochrosite is a very, fragile stone. The Mohs hardness varies between 3.5 and 4. This means that a file can damage the stone easily. If its indeed gem quality, it could be very hard and expensive to replace. The emerald cut setting is one of the harder styles to set properly. Have you set many colored stones?

Sometimes it’s best just to pass on the job, rather than own it forever.

Tjones

Some of my work

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Thank you Tjones!
We have set many fragile stones; we agree with you to pass on the job! We think they spent almost $3800.00 on this beautiful stone. So many clients buy beautiful stones at the Tucson Gem Show but have not idea how fragile the stone might be.
Many Thanks for your wisdom!
Ursula

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I have only ever cut and set semi-precious Rhodochrosite. While very pretty, in my experience, it is very fragile and hard to work with. Tjones, I like your work…Rob

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Thank you for your reply. We have reached out to our client and we’ll see where this goes…
Ursula

As a faceter as well as a dilettante jeweler, I agree that this is a collector’s stone that should be in a case and not set and worn. If the owner has to wear it, I would encourage a pendant rather than a ring for less wear. It could be set down into a hemispheric piece of metal that would keep most objects from reaching it and this — or something like it — is what I would recommend if they absolutely HAVE to have it set. As far as setting it, some opal and emerald setters use some tricks and don’t pull the prongs all the way down. They then put a tiny amount or epoxy or gel superglue under the prongs to hold the stone. You can apply the glue with a syringe or similar and then wipe off any excess before it sets. I am guessing that rhodochrosite is not porous enough to absorb the glue, but you’d have to check gemology texts to be sure. It might also be possible to set the stone in a very thin bezel that pushes over with very little pressure.

All that said, I would discourage this person from wearing it and especially from wearing it regularly in a ring. Even set down in a dish, there is always the possibility of a sharp object going into the dish. A car door handle or other door handle could do that or an object in the kitchen. You can tell the client that when tanzanite was first discovered, a lot of people put it in rings and after a while its popularity waned just because it was so easily scratched in rings. And tanzanite is Mohs 6 to 6.5 in hardness!

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Thank you RoyJohn for your reply. It looks like a beautiful “specimen” from Alma Colorado, The Sweet Home Mine. Your suggestions will be taken inconsideration! Thanks again, Ursula

Ursula, thanks for your kind words…I think I remember one of the guys involved with that mine being at a Gem Show here in Knoxville exhibiting rhodochrosite, both faceted and cabbed and rough/specimens back a long time ago, maybe in the 80’s or 90’s. From what I see on line, the Sweet Home Mine is still producing, but I don’t know what’s coming out of there now, couldn’t find any on line info. There is someone selling Sweet Home rhodochrosite on Etsy, but it could be old stock. I did see where as a mineral rhodochrosite is rated as brittle and has one perfect cleavage, which would be two more reasons not to wear it in jewelry. But it is a pretty, distinctive color, so I can understand wanting to do that.

There are some hobby faceters who want to facet all the rare and soft gems, even those with perfect cleavages, which easily open up cracks in faceting. I have enough trouble cutting the standard gems that can be set in jewelry or sold to other jewelers, so I pass on rhodochrosite, apophyllite, cuprite, etc.

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FWIW, in my old boss’s shop we always set emeralds with 22K prongs. Partly because they require less force to push over the stone, though still quite strong enough to hold it. But mostly because the warmer color better complements emeralds than either French or Italian color 18K.

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GemQuality
RoyJohn this is a really nice stone from the Alma Mine in Colorado. Sweet Home Mine in Co, as you said.
Right now it sounds as though she is willing to just look a the stone for awhile…Thank you again for your information! Ursula

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Elliot, We suggested the same thing to our client…using 22KT dead soft prongs or tab set. We have told her that a ring is definitely not going to happen. A pendant would be all we’d be willing to do…if we do anything at all. Right now she is “sitting on it”. I think we burst her bubble! Thank you for your reply! Ursula

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That is a very pretty stone…as a gemologist I was ogling it and wishing the picture was a little more of a close up, but from what I can see it is quite transparent and I don’t know for sure, but I think really transparent rhodochrosite is pretty rare. If she really likes faceted stones and designing jewelry pieces, maybe you should turn her on to some of the American precision cutters who have websites. One of those is my friend Dan Lynch, but there are several others. Lots of real quality goodies at decent prices…

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Hi! This client works the Tucson Gem and Mineral Show…she loved the clarity snd quality of the stone; never thinking about its soft properties. The Gem stone is in Houston, I’ve not personally seen it. Thank you again! URSULA

So she can find whatever she wants! Good for her! Now if she only knew what to buy! I’m seeing a 2.9ct faceted rhodochrosite at Gem Rock Auctions for $300 with two google clicks. A few inclusions, but very nice clarity. So what she bought is probably available at $600 or less. IDK if the Sweet Home provenance is worth anything or not, but certainly not thousands. Maybe you shouldn’t tell her…LOL…you should buy that one on GRA and con her into a custom designed pendant set with both of them…LOL…

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soft brittle stones never belong in a ring of all places!.. tell them that any slight mishap could destroy it!
better seen than worn… if set, a piece that is less likely to be damaged, like earrings or a pendant would do…
rhodochrosite MgC03, forms a solid solution with siderite, FeC03 and also zinc and Ca to a lesser extent. the type locality was from a a silver mine in Romania. It’s found in low temperature lead- silver hydrothermal veins and rarely in pegmatites…Gem crystal type locality in the US is the Alma mine in Colorado…the harness is 3.5 to 4 on the Mohs scale. it’s crystal structure is trigonal, weakly birefringent and it belongs to the calcite group of minerals…clear crystals are beautiful, difficult to cut due to their softness. details of it’s optical, chemical and physical properties can be found on www.mindat.org

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Hi jsfandskh,

Telling clients to not buy “pretty stones” is like telling a kid they can’t have ice cream after they finished their dinner…
This purchase was purely “…I love that color, what a beautiful stone, I’d love that in a ring…” And the unfortunate part is the stone cutter sold it to her knowing she wanted it in a ring and gave her a discount to land the sale, and never explained that is was super soft…
Thank you for you link to www.mindat.org
Ursula

The only way I would even consider that in a ring is if I designed something that basically put it inside a cage within a cage (bending metal around it) – so any and all impacts would hit the metal on the outside and never reach the stone inside. Even with that, it’s just so tricky to set in such a way that it will show off its quality. It needs light passing through to really make it shine, and not much that would be protective enough to keep it from damage is going to work for that unless you do some really fancy (and expensive) designing.

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Hi 4 hands!.. clear deep red/purple manganese colored stones are truly beautiful… manganese as a coloring agent is very rare in the mineral kingdom…hard durable stones that have Mn as a colorant, that are deep red/purple include spessartine garnet which is a solid solution garnet with Fe and Mg, with pyrope being the the end member with Mg, and almandine being the Fe end member…Morganite beryl is Mn colored but very light pink, rhodonite is a pink Mn pyroxenoid inosilicate, which is brittle, red spinels I think are colored by Mn also, Violane, which is Mn diopside (chromium diopside is more familiar as a green gem)… diopside is a complex clinopyroxene with Ca and Mg being the primary end members in solid solution with ferrosilite being the Fe end member… it also is in solid solution with Augite which is even more complex, containing Na, Ca, Al, and Ti…High Na Augite becomes undersaturated with respect to silica and grades into Jadeite… which can take any color, including purple form Mn any of these red/purple Manganoan gems would far harder and tougher than Rhodochrosite for setting in a ring, But as you say it’s a kid being denied ice cream or a sparkling bit of irresistible candy…the seller was irresponsible for NOT telling her that it was unsuitable in a ring. Any of these other stones would have been more appropriate but also quite expensive.

The pyroxene family of minerals has only a few gem members which makes them rare and expensive. Orthopyroxenes do not form gemstones, their crystal structure is orthorhombic, clinopyroxenes are monoclinic and are important rock forming minerals in the lithospheric mantle… as they are stable at high pressures. They are also aluminous. Feldspars, particularly plagioclase contains aluminum and at a depth of 70km, the lithostatic pressure compresses the atoms closer together, kicking up the coordination number of Al from 4 to 6, that transforms it into a denser garnet structure…Jadeite is a high pressure Na end member of the the clinopyroxene family. It exists in solid solution in titanium augite in high Na, alkalic volcanic rocks. Alone, it’s only found in high pressure, low temperature metamorphic rock belts…

I’ve worn many hats during my long career as a subspeciality neurologist… from which I’m retired (partially),

I learned jewelry making in high school… and made quite a few pieces with only hand tools… but that was long ago… I can’t sit at the bench anymore due to neck problems and failing eyesight due to growing old… my hobbies were rock collecting as a kid, which then went into wanting to learn about them, so I studied mineralogy, then igneous petrology and geochemistry. Instead of collecting rocks, now I collect geochemical papers… plain old drab rocks can tell us how the earth evolved from the time of it’s accretion in the solar nebula to to the present…but I’m just an amatuer…most of this stuff is PhD stuff, that requires physical chemistry, chemical thermodynamics and phase changes, and higher math to understand symmetry groups that are essential to understanding crystal structure… .I know a lot but not enough to really understand the complexities of mineralogy and the transformations at higher temperatures and pressures.

I’ve also collected gems, buying them a long time ago when they were cheap… the prices have gone up ten fold for colored stones…good quality large precious stones cost in the 10K to 50K range… what’s available now for cheap is of very poor quality. gemology for me has been an extension of mineralogy…

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