Is moonstone hard to get right?
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Author:  bruce_tourm [ Sat Jun 01, 2019 5:25 pm ]
Post subject:  Is moonstone hard to get right?

I use to subscribe to the Gem Guide and they still send me brief articles describing some gemstone electronically. I just received their June production. It is labeled.

Gem World International June 2019 Featuring Moonstone.

Short of a brief discussion on the present prices of moonstone, it really is for a person who is very new to gemology, in my opinion. As I was skimming it, I ran into the following statement that really makes me wonder who writes and reviews this "educational" material.

"Fine and transparent examples of moonstone may be faceted, but due to Feldspar's low HARDNESS, they won't display the best BRILLIANCE."

The capitulation is mine so I can make my point clearer.

I hope you reflect on this authoritative statement and realize that they mean index of refraction rather than hardness. I guess that it is an easy mistake to make, but it does not fill me with confidence in their effort to get things right. I bet one of their articles on Paraiba tourmaline would be a humdinger.


Author:  Stephen Challener [ Sat Jun 01, 2019 9:26 pm ]
Post subject:  Re: Is moonstone hard to get right?

It is probably just a typo introduced during editing--originally it probably discussed both its relatively low hardness (for ring usage anyway) and its relatively low refractive index, and accidentally got shortened into the current phrasing.

Author:  TheL [ Thu Sep 10, 2020 7:33 pm ]
Post subject:  Re: Is moonstone hard to get right?

Maybe a typo but maybe not?

Low hardness could also mean not the best polish can be achieved, which would affect its reflectance properties and cause less then optimal "brilliance"?

Author:  glhays [ Thu Sep 10, 2020 8:15 pm ]
Post subject:  Re: Is moonstone hard to get right?

I would agree with Stephen, Brilliance is going to be more a refractive index issue than hardness. Moonstone takes a very good polish even when faceted. Seems like the article may have just been transposed in error. I have polished many moonstone cabochons and faceted quite a few as well. No special technics are necessary or tools. Reflections will not effect brilliance.

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