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Lowest mohs hardness for rings? Other decisive factors?

RedSpinel

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I didnt have enough room in the title area to really spell out the subject I'm asking people's opinions on. What I'm wondering is what is the least/lowest mohs hardness that YOU will accept when deciding which gems to mount into a ring? Also, there are other, non hardnesss related issues that might also effect your decision on whether to choose certain gems for mounting in a higher wear jewelry setting like a ring. So its overall toughness thats important, and not just hardness because hardness doesnt tell the whole story.

I originally had read that you should want at least a hardness of 7 or so for rings, but then I saw countless Tanzanites being mounted in rings, even though they are only around 6.5. That means if you arent careful, that your 5+ ct royal blue Tanzanite is likely to be scratched or suffer wear at the facet edges, etc.

But there are other "issues" that seem to come up when choosing gems for their durability for mounting in higher wear type mounts. Even though Topaz has a nice hardness of 8, it apparently has cleavage issues from what I've read in the past. So if you mount a super nice, rare Imperial Topaz into a ring, then you accidentally slam your hand up against something, the Topaz might simply cleave into 2 pieces or more. Supposedly Zircon has fairly similar issues with brittleness, and is some times difficult to facet and polish because the edges or points might chip, or if you knock it against something. A large diamond might even suffer some cleavage related damage if hit hard enough. The cutters usually cleave them at the beginning to get at the best piece of rough. I believe Tourmalines have some issues as well.

Then there's Emeralds, which are likely to have internal weaknesses due to their omnipresent inclusions, which might be an issue if knocked hard against an object. Rubies are no doubt similar due to their always present inclusions.

So that leaves us with sapphires and especially Spinels! Yaaay! No I think certain Garnets are probably hard enough and tough enough to be mounted into rings. As is Chrysoberyl, and other beryl gems.

What is your criteria for toughness, and how/where would you mount the less tough gems? Whats the lowest hardness for rings in your opinion?

Lastly, have you ever suffered any wear related issues with gems that werent as tough or hard in your jewelry?
 

Kim Bruun

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RedSpinel|1340254176|3220844 said:
As is Chrysoberyl, and other beryl gems.

You should careful lumping chrysoberyl and beryl together, as they are not really related. Chrysoberyl has a hardness of 8.5, and is thus the third hardest natural gemstone known to man. Beryl has a hardness of 7.5 to 8, so it is softer than chrysoberyl, and, I understand, also more brittle.

Some pricescopers will tell you the only four gems suitable for rings are spinel, sapphire & ruby, chrysoberyl, and, of diamond, but that doesn't mean that you can be as wreckless as you want with these four. Any gem can chip, though some are more brittle tan others. That said, jadeite and, even more so, nephrite are famously tough, so you might consider those for rings as well - my mother has a jadeite ring, several decades old, and the stone still looks nice.
 

chrono

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You are quite right to consider other factors like internal inclusions / fractures, brittleness and cleavage planes as well, which leaves only a few varieties open as to everyday wear stones for rings. Of course, these are not full proof either as there are cases where diamonds are chipped beyond recognition. It's all about how they are worn.

A beryl (aquamarine, morganite and emerald among others) is not a stone that I would consider as an everyday wear ring with a different SG, RI and toughness from a chrysoberyl, which is of a different gemstone type.

Softer or less durable stones are best set as pendants, earrings and brooches. Bracelets take a lot of abuse and only the big 4 (sapphire, diamond, spinel and chrysoberyl) should be set as a bracelet. Of course, other type of gemstones can be worn as a bracelet but only with care and for special occasions.

Kim,
Excellent point about jadeite. They are surprisingly tough due to their internal structure.
 

stargurl78

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I always thought that since I was very careful with my rings, I could put whatever stones I wanted to into them and they would be fine. Nope, wrong. I have an asscher peridot ring (6.5-7 on the Mohs scale?) and I chipped off one of the corners of the table (or it may have been chipped during setting but I'm not sure). You really can't tell unless you're looking really hard so I still wear the ring regularly.

I probably wouldn't go any lower than 6.5.
 

Roger Dery

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Hi Red Spinel,
What I'm wondering is what is the least/lowest mohs hardness that YOU will accept when deciding which gems to mount into a ring?
You've asked a great question, and one that wearer's of jewelry the world over have wondered. So maybe I can add some to the dialog and everyone can benefit. As a company, we have handled just over 7,000 recuts, refurbishing or repairs of colored stones. So what I am offering here is strictly anecdotal from our experiences. *addressing transparent faceted gemstones.

Mohs 9 - Ruby and Sapphire: generally considered the most durable of the colored gems. If untreated in any way, will hold up very well in most all situations. Even those subjected to 'high-heat-only' still do very well. Example: my wife's 2ct oval Sapphire engagement ring was worn daily for 15 years before needing a very minor tune-up. Exception: Ruby that has been filled with substances such as glass have a much lower resistance to damage such as abrasion from wear. Ruby, under high-heat-only with flux present, will also handle wear well.

Mohs 8-1/2 - Chrysoberyl including Alexandrite: in my experience Chrysoberyl holds up very well against wear. It does not exhibit severe brittleness seen in other gems - and would be a great stone for regular wear as a ring stone.

Mohs 8 - Spinel: is generally considered a gem that wears well. It is resistant to damage and not just damage from abrasion.

Mohs 8 - Topaz: can be worn in rings, but some caution should be exhibited. This is especially true with Topaz colored blue because it has been irradiated [and then subsequently heated]. This process has weakened the stone in some way that it does not hold up as well as Precious Topaz - which may, or may not have been treated at all.

Mohs 7-1/2-8 - the Beryl family including Aquamarine, Heliodore (golden Beryl), Morganite, Goshenite wear fairly well and unless totally exposed from the metal, can be worn in rings though may not be suitable for 'everyday wear'. The heating of any of the Beryl's is done at a low temperature and it is not a factor regarding their durability. Beryl's do have an element of brittleness though not as severe as some other gems.

Mohs 7-1/2-8 - Emerald (of the Beryl family) is not well suited for everyday wear. A totally clean Emerald will hold up as well as an Aquamarine. But, finding an Emerald with that level of clarity is extremely rare. Roughly 99% of all Emeralds have been treated with a filler of some type to (usually) improve their clarity. The filler is likely to not hold up well over time. *Emerald's that have been treated should not be placed into an Ultrasonic cleaner, nor placed under a steam cleaner as this may affect the clarity enhancement substance. **Caveat: Emerald's treated with a specialized process known as "Excell" in the trade are known to have a higher level of durability over those treated with other methods.

Mohs 7-1/2 - Andalusite has reasonable wearability though it does have a slight brittleness. Facet junctions are likely to show wear after only a few years regular wear. Distinct cleavage is present in Andalusite though I have yet to see the affects of it.

Mohs 7-1/2 - Iolite in my experience holds up fairly well for hardness 7-1/2. It does, however, have distinct cleavage and a sharp blow in one or more specific directions may cause it to separate into more than one piece. Though, when I have tried to do this in the rough, I have not been successful.

Mohs 7-7-1/2 - The Garnet group is generally thought of as reasonably durable. Facet junctions will show wear within the first few years of being worn. And, the facet junctions may not chip as much as 'crumble' for lack of a better way to describe this. Of the Garnets, the Andradite/Demantoid type is the least durable, and we have found the Pyrope/Almandine/Spessartite group seem to wear slightly better.

Mohs 7-7-1/2 - The Tourmaline group is suitable for rings, though not for everyday wear especially if the top of the stone is exposed. Tourmaline can be brittle, does not hold up well where temperature changes are radical. They are known to be 'chippy' as can be seen along facet junctions that are exposed.

Mohs 6-1/2 to 7-1/2 - Zircon is often thought of as brittle. Zircons heated to high temperatures (over 1,000*C) to convert them to blue are definitely more brittle and show the effects of wear easily. Blue Zircon worn high on a mounting will need refurbishing regularly. Unheated Zircons and those subjected to much lower temperatures (of various colors) are less prone to show wear - and appear less brittle. There is no known dilemma with faceting or polishing Zircon for the experienced lapidary. There is, however, a known direction to its hardness which could create difficulty for some.

Mohs 7 - The Quartz family is well known due to being available and popular. Its wear pattern is predictable. Facet junctions (even when faceting) can be 'chippy'. Chipping along the crown facets is common, and abrasions from wear are as well.

*as a general rule, at least from me, I don't suggest wearing hardness less than 7 on a regular basis as the wear will become evident well before you expect it. I do suggest moving this type of gemstone into mountings offering great protection or off the fingers or wrist.

Mohs 6-1/2 to 7 - Kunzite is not a durable gemstone. It is brittle, does not resist scratching well, does not repair easily, and has perfect cleavage in two directions. In addition to all that, it has the unfortunate problem of being light sensitive - reducing its depth of color with prolonged exposure to direct sunlight. I have repaired my fair share of Kunzite's and I don't relish the fact that they show up waiting for my handy work. But since they don't wear well over time, they will all eventually need reconditioning.

Mohs 6-1/2 to 7 - Peridot does not share the fate of Kunzite, though its wear pattern is predictable. Abrasions are readily seen on exposed gems that are frequently worn - and fortunately, a refurbishing is not usually problematic.

Mohs 6-1/2 to 7 - Tanzanite is very popular and goldsmiths have taken to mounting them in lavish and risky ways. Exposed surfaces will show wear in a relatively short time and the perfect cleavage can be a problem. Tanzanite is also heat sensitive - even though it is well known to have been heated to acquire the beautiful blue to purple hues. It is the shock of rapid temperature change that may cause damage. This is not a common situation with consumers as this is more likely to take place in the creation or repair to a mounting.

Mohs lower than 6-1/2 - Apatite, Opal, Orthoclase/Sunstone, Scapolite, Sphene and Sphalerite and other low hardness gems all need special care to be worn in rings. It is generally accepted that these gems are best suited for pendants, pins, brooches or earrings.

I hope you find this helpful.
 

Kismet

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Awesome post Roger. It should totally be stickied.
 

chrono

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With permission, I am going to cut and paste it in the New to Gemstones sticky with credit to Roger.
 

Enerchi

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Thank you Roger! That was VERY helpful! I've cut and pasted that to my computer!!! Thanks for all that information in one spot.
 

T L

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Roger Dery|1340284668|3220963 said:
Mohs lower than 6-1/2 - Apatite, Opal, Orthoclase/Sunstone, Scapolite, Sphene and Sphalerite and other low hardness gems all need special care to be worn in rings. It is generally accepted that these gems are best suited for pendants, pins, brooches or earrings.

Thanks RedSpinel for the good question and thanks Roger for the detailed answer.

However, some gems, like sphalerite that you mention above, are so soft, I don't even think they can be set, can they??? The most beautiful stones I've ever seen were some sphalerites, and I wish the were harder. I think they're a 3.5 on the Mohs scale, and must be handled with great care. I can't even see them being placed in metal.
 

Kismet

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TL|1340291481|3221030 said:
Roger Dery|1340284668|3220963 said:
Mohs lower than 6-1/2 - Apatite, Opal, Orthoclase/Sunstone, Scapolite, Sphene and Sphalerite and other low hardness gems all need special care to be worn in rings. It is generally accepted that these gems are best suited for pendants, pins, brooches or earrings.

Thanks RedSpinel for the good question and thanks Roger for the detailed answer.

However, some gems, like sphalerite that you mention above, are so soft, I don't even think they can be set, can they??? The most beautiful stones I've ever seen were some sphalerites, and I wish the were harder. I think they're a 3.5 on the Mohs scale, and must be handled with great care. I can't even see them being placed in metal.

I know Barry at ACS had sphalerite studs for sale at one point. And Brad at the Gem Trader had a rhodochrosite pendant for sale as well. You just need to find a benchman with nerves of steel.
 

Tanzigrrl

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I routinely wear an emerald ring, an opal ring, and a tanzanite ring, depending on the day. I am also excessively careful and aware of my movements. I sit at a computer all day. I take off my rings when I am at home and am likely to do dishes, gardening, or the like. I'm very, very, very careful. I know well the risks of wearing these stones in rings and I go about wearing them carefully. I don't feel "bullet-proof" but I don't feel like I'm "living dangerously" either.
 

Roger Dery

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TL|1340291481|3221030 said:
Roger Dery|1340284668|3220963 said:
Mohs lower than 6-1/2 - Apatite, Opal, Orthoclase/Sunstone, Scapolite, Sphene and Sphalerite and other low hardness gems all need special care to be worn in rings. It is generally accepted that these gems are best suited for pendants, pins, brooches or earrings.

Thanks RedSpinel for the good question and thanks Roger for the detailed answer.

However, some gems, like sphalerite that you mention above, are so soft, I don't even think they can be set, can they??? The most beautiful stones I've ever seen were some sphalerites, and I wish the were harder. I think they're a 3.5 on the Mohs scale, and must be handled with great care. I can't even see them being placed in metal.
TL - you're welcome.
In my opinion, Sphalerite is one of the most beautiful gems to view. It does however require extreme care to wear one. And it is the rare stone setter who will entertain working with it. Most of the stores I work with give me the 'evil-eye' if I propose selling or setting a Sphalerite. Its reputation as delicate gem is well-deserved.
 

ChrisA222

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Roger,

My only comment was on the Sunstones..I thought that the Oregon Sunstones were more durable than the rest of the Feldspars...with hardness along the same lines as quartz...at least that is what I was told...can you expand on Sunstones/Oregon Sunstones? If anyone knows, it is you!
 

Roger Dery

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Chrisa222|1340297431|3221103 said:
My only comment was on the Sunstones..I thought that the Oregon Sunstones were more durable than the rest of the Feldspars...with hardness along the same lines as quartz...at least that is what I was told...can you expand on Sunstones/Oregon Sunstones? If anyone knows, it is you!
Hi Chris,
I've cut Orthoclase, Bytownite, Oregon Sunstone, Sunstone from Tanzania Oligoclase from China - all in the Feldspar Group. "In my opinion" they react the same on the wheel. They are easy to cut and take a very nice polish. In most gem reference books, including the Handbook of Gem Identification by Liddicoat, it is stated that their Mohs hardness is: 6 to 6-1/2. In "Gems" by Webster and Anderson it states that Oregon's variety of sunstone is at hardness 6.

Now, it is possible, that in one or more directions the hardness shows up as slightly harder. But in my experience it facets similar to Scapolite, Peridot, and Tanzanite - all of which are at or near 6-1/2.
 

T L

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Roger Dery|1340293544|3221057 said:
TL|1340291481|3221030 said:
Roger Dery|1340284668|3220963 said:
Mohs lower than 6-1/2 - Apatite, Opal, Orthoclase/Sunstone, Scapolite, Sphene and Sphalerite and other low hardness gems all need special care to be worn in rings. It is generally accepted that these gems are best suited for pendants, pins, brooches or earrings.

Thanks RedSpinel for the good question and thanks Roger for the detailed answer.

However, some gems, like sphalerite that you mention above, are so soft, I don't even think they can be set, can they??? The most beautiful stones I've ever seen were some sphalerites, and I wish the were harder. I think they're a 3.5 on the Mohs scale, and must be handled with great care. I can't even see them being placed in metal.
TL - you're welcome.
In my opinion, Sphalerite is one of the most beautiful gems to view. It does however require extreme care to wear one. And it is the rare stone setter who will entertain working with it. Most of the stores I work with give me the 'evil-eye' if I propose selling or setting a Sphalerite. Its reputation as delicate gem is well-deserved.


Thanks Roger,
It's a real pity because I find them more beautiful than diamond when well cut and clean.

http://www.youtube.com/watch?v=IyioYMrHICs&list=UUx116P3ySHdD2zVH2LWdhEQ&index=7&feature=plcp
 

LD

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There is no real answer to your question because it depends on very personal factors:-

(1) How light/heavy you are on your rings;
(2) If buying loose stones and getting them set, you have a setter you trust and who is skilled;
(3) Your attitude to risk!

I have rings with Apatite, Opal, Sphalerite, Zircon, Sphene etc and I wear them regularly (although not daily). I am very light on my rings and so far (touch wood) haven't damaged anything. However, I seem to be in the minority and more often than not collectors are much more conservative about what they will put in a ring and wear.

My philosophy is that these beautiful gems were made to be worn and admired not kept in a case!
 

RedSpinel

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To Kim Bruun: Actually, I didnt lump beryl and chrysoberyl together into the same family. If I had lumped them together, I wouldnt have called them by their separate family names(ie beryl and chrysoberyl). I am fully aware that they different hardness. But the point was that other Beryl family gems dont have the inclusions that Emeralds have, and therefore might be better suited for high wear settings, because they dont have the ever present internal inclusions or fillers that emeralds have.

The ring I wore the most frequently was NOT treated in a sensitive fashion! My(now lost) star sapphire in a very thick 14kt gold mens ring was worn every single day for nearly a decade, and since I own a landscaping co., I was out working in that field daily, and I didnt take it off. Or at least I almost never took it off. I would dig large holes to plant shrubs, trees, etc while wearing it, I would prune shrubs, you name it. I had it polished(the gold) fairly regularly, which was kinda stupid considering that I was just going to wear off the polish in a few months anyway. But.... the sapphire in that ring never showed the slightest signs of scratching, chipping, losing its polish, or anything!

Then it got lost somehow about 1 year ago, and I dont know how or where.... There went $1000++...(actually, if I were to buy that same, thick gold ring now, it would probably cost in the neighborhood of $1500 just for the setting, plus the sapphire, and it would be more than $2000)
 

chrono

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Cabochons always hold up better than their faceted brethren because there are no sharp angles or corners to get chipped off. This is why some softer stones can be set and worn as rings if cabbed instead of faceted.
 

T L

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LD,
Do you have a photo of your sphalerite ring. If I could set a sphalerite, I would do so in a heartbeat. Considering that glass is a 5 on the Mohs scale, and sphalerite is around a 3, it terrifies me to set something so soft.
 

RedSpinel

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TL|1340382080|3221853 said:
LD,
Do you have a photo of your sphalerite ring. If I could set a sphalerite, I would do so in a heartbeat. Considering that glass is a 5 on the Mohs scale, and sphalerite is around a 3, it terrifies me to set something so soft.



For some reason I didnt realize that Sphalerite was THAT soft! I would really worry about mounting it in any jewelry that would be worn more than only very rarely, and never into a ring or bracelet.
 

Roger Dery

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While Sphalerite is soft, it also has 'perfect' cleavage in 6 directions - and this is likely more problematic for the goldsmith - stone setter.

According to the following references, Sphalerite is:

3-1/2 to 4: GIA A & B charts
3-1/2 to 4: GIA Gem Reference Guide
3-1/2 to 4: Handbook of Gem Identification by Liddicoat
3-1/2 to 4: Webster & Anderson's Gems, their Sources, Descriptions and Identification

If you are able to convince someone to set a Sphalerite for you, it would be unreasonable to expect them to guarantee the project's completion. It is a delicate gem and requires someone who has existing experience working outside the mainstream of gems.
 

minousbijoux

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Roger Dery|1340466393|3222407 said:
While Sphalerite is soft, it also has 'perfect' cleavage in 6 directions - and this is likely more problematic for the goldsmith - stone setter.

According to the following references, Sphalerite is:

3-1/2 to 4: GIA A & B charts
3-1/2 to 4: GIA Gem Reference Guide
3-1/2 to 4: Handbook of Gem Identification by Liddicoat
3-1/2 to 4: Webster & Anderson's Gems, their Sources, Descriptions and Identification

If you are able to convince someone to set a Sphalerite for you, it would be unreasonable to expect them to guarantee the project's completion. It is a delicate gem and requires someone who has existing experience working outside the mainstream of gems.

Roger:

Thanks so much for all your information. This, particularly, I found facinating. Perfect cleavage in 6 directions - yikes!

LD: how in the world did you ever find someone to set it for you?!
 

jstarfireb

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I know I am different from the majority here, but I will set any stone in a ring provided that it's inexpensive. And all of the stones I buy are what I consider inexpensive, because I won't spend more than $200-300 on a colored stone. I have rings set with apatite, opal, tanzanite, benitoite, zircon, demantoid, and other soft stones. I like to see my stones, and a ring is the best way to showcase them to myself.

I prefer variety in my collection and have enough rings that I only wear each one occasionally, and I typically don't wear my more fragile rings to work. My engagement ring has a diamond, but if I were choosing a stone for an engagement or otherwise everyday ring, I would consider sapphire, chrysoberyl, spinel, or maybe garnet.
 

minousbijoux

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You go, Jstar!
 
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