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An interesting article from Gemfix

faegrace

Shiny_Rock
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Feb 24, 2011
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Aaahh, The MOHS’ “Hardness” Scale
By Laura Gulij

The Mohs’ Scale of Hardness has been called “relative” and even “arbitrary” by experts in gemology and geology. Why? Read on and see if you don’t agree…
A little history lesson: in 1812 Frederich Mohs selected 10 minerals that were common (in 1812), and arranged them from 1-10 based on scratch tests. As in, number 10 could scratch number 9, number 9 could scratch number 8, etc. 1 is talc, 10 is diamond.
This table is not equally divided, for example a diamond is a “10” and sapphire and ruby are “9”, but diamond is actually 400% harder.
For years, jewelers and the general public have been using this scale like a purchasing bible to determine “hardness” of gemstones. But is ease of scratching the same as toughness? Is a stone that scratches easily a “soft” stone? Is a stone with a higher Mohs number a “tougher” stone?

Some Examples:
Mohs’ Scale: 6-7 GLASS- Think about how tough a GLASS car windshield has to be, or a champagne bottle.
Mohs’ Scale: 5 Your TEETH- “Softer” than Opal, (5.5) With a little care, most of us can get by with the same set for 70 years or so.
Mohs’ Scale: 7.5-8 EMERALD- “Hard” right? Don’t put a large Emerald in a prong-set ring, too brittle. We’ve repaired or replaced lots of those! “Hard” but definitely not TOUGH.

How about this one, Everyone knows PLATINUM is really tough, right? My Grandmother’s ring still looks brand new. Yet, at only 4.5 on the Mohs scale, it is “softer” than practically every gemstone!

So this is what it boils down to: don’t confuse “toughness” with Mr. Mohs’ scale of “hardness”.
To a gem cutter (and repairer), it is all about wearability. For a stone to be a good choice for a ring, it has to be “tough”, not the same as “hard”.

Our top 10 “tough” colored stone recommendations:

Corundum: Ruby, Sapphire,
Garnets: Spessartite, Demantoid,
Zircon
Aquamarine
Spinel
Peridot
Tourmaline*
Tanzanite*
Quartz:* Citrine, Amethyst
Iolite*
*All suitable for rings, but probably best to keep prong settings low, or use somewhat protective settings, ie., low prongs, bezels or channels.

Of course, you can wear anything you want! Especially if you wear a ring occasionally, have the stone protectively set, and/or are very careful. I love my opal channel set ring, have had it 15 years, and still don’t have a scratch on it.
Don’t feel tied to an outdated method of categorizing “wear-able” stones with those to “avoid like the plague”. If you like it, wear it! Just take the proper precautions and you can enjoy it for a lifetime. Like your teeth.
© Gemfix 2011
 

movie zombie

Super_Ideal_Rock
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Jan 20, 2005
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nothing that i'd argue with....and kept short and to the point. good post!

MoZo
 

faegrace

Shiny_Rock
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Feb 24, 2011
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373
MoZo ~

I thought so as well. Other than it made me want to go out and buy a tanzanite for a low setting.... :cheeky: I do love that violet I cannot seem to find elsewhere....

~ faegrace
 

athenaworth

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faegrace|1305946475|2927037 said:
MoZo ~

I thought so as well. Other than it made me want to go out and buy a tanzanite for a low setting.... :cheeky: I do love that violet I cannot seem to find elsewhere....

~ faegrace
Made me wanna buy an apatite
 

jstarfireb

Ideal_Rock
Joined
Mar 24, 2007
Messages
6,232
I'm surprised to see both zircon and tanzanite on a list of tough stones. They're both prone to abrasion...

(ETA: I put them in rings all the time, though!)
 

Michael_E

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[quote="faegrace|
Our top 10 “tough” colored stone recommendations:

Corundum: Ruby, Sapphire,
Garnets: Spessartite, Demantoid,
Zircon
Aquamarine
Spinel
Peridot
Tourmaline*
Tanzanite*
Quartz:* Citrine, Amethyst
Iolite*
*All suitable for rings, but probably best to keep prong settings low, or use somewhat protective settings, ie., low prongs, bezels or channels.

[/quote]

Zircon, peridot, tourmaline, tanzanite and the quartz stones definitely do not belong on that list as they are all quite a ways from what I would call "tough". Tanzanite in particular is soft and brittle making it a poor choice for an exposed stone in ring regardless of how it's been set. This list must have been made up by someone who had too many of these stones and needed to sell some of them because it's way off the scale as far as sales hype.
 

Aoife

Brilliant_Rock
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Jun 23, 2010
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I really don't agree with this list. I suppose it all depends on your definition of "tough," but no matter what your definition is, I don't think Tanzanite and zircon belong on a list of tough stones. And aquamarine? Really? :-o
 

faegrace

Shiny_Rock
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Feb 24, 2011
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It is fascinating to read people's opinions on this....

I am not one for owning much of anything that doesn't get regularly worn, used, etc. (My grandmother had so many things she saved for "someday" and "special occasions".., such a waste in many ways.) So, I guess if I were to choose gems based on agreed-upon wearability, I would be be rather limited. Hmmm.
 

movie zombie

Super_Ideal_Rock
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Jan 20, 2005
Messages
11,879
personally, i think we get hung up on the moh scale way too much. i have huge jasper cabs set in silver that according to the moh they should be shredded by now. but they are not. true, they are not faceted but i'm rough with my hands and i knock them around quite a bit.

i don't wear my spess 24/7 but i do wear it to the garden center, the farmers market, etc.

i have an aqua that i used to wear daily until i was sitting in a bar one night and while talking waved my hand into the wall and chipped it.

i have a friend that wore her peridot [however it was bezel set] daily w/o problems.

i will admit i also am too hung up on the moh but i think the article is a good reminder that stones were meant to be enjoyed.

MoZo

ps diamonds are not impervious despite the moh number nor are sapphires. i've seen a sapphire e-ring worn 24/7 for 20 years that didn't have a facet left.......however, its each to their own.
 

Aoife

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Joined
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Personally I believe in wearing and enjoying the gemstones I purchase and set, whether they are diamonds or opals. I think there is a difference, though, between a gemstone being wearable, and it being tough. The Gemfix article did give a nod to the idea that some gemstones need to be worn with care, but to list Tanzanite, iolite, etc under the heading Top Ten Tough Gemstones is misleading, especially to people who are new to colored gemstones. Of course it's possible to damage a diamond, or a sapphire, but it is much, much easier to damage a tanzanite or zircon, and the list does a disservice by, IMO, implying otherwise by listing them all together.
 
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