Find your diamond
Find your jewelry
shape
carat
color
clarity

Concave cutting in spinels

YadaYadaYada

YadaYadaYada

Super_Ideal_Rock
Premium
Joined
Feb 2, 2016
Messages
12,154
I came across a mahenge concave cut stone in my travels and its the first I've seen with this cut, is this because the cut itself is not popular or because it is not desirable with spinels in particular?

Is there a specific concern with this cut like more likely to exhibit extinction or some other less desirable trait?
 
Hi, Stephanie

It's my impression that most people are not indifferent to concave cuts: they either are intrigued by-really like them or they don't care for them. Here's a lengthy post from long ago that I think you'll find interesting and helpful; also, scroll down to post #23 for additional feedback from Wink:
https://www.pricescope.com/communit...-stone-purchase-from-homer.48742/#post-730096

P.S. I'd be very leery about a concave cut gem that's particularly susceptible to abrasion (e.g., amethyst and tanzanite) .. but I don't know if anyone else shares my concern ; - )
 
Interesting thread, thanks for sharing Molly! I try to stick with a hardness of 8 or above but I have seen some beautiful concave cut amethyst stones, not for me but very pretty.
 
IMG_20171112_113334.jpg I have two concave cuts, blue topaz and white topaz. Very hard to photograph.
They are so much more beautiful in real life.
 
stracci2000 said:
IMG_20171112_113334.jpg I have two concave cuts, blue topaz and white topaz. Very hard to photograph.
They are much more beautiful in real life.
Click to expand...

They are both gorgeous but I love that white topaz! Do you think the concave makes for a quieter stone or do they still sparkle?
 
IMG_20171112_115212.jpg
StephanieLynn said:
They are both gorgeous but I love that white topaz! Do you think the concave makes for a quieter stone or do they still sparkle?
Click to expand...
No, they flash like crazy! They are very lively. It's like there is a starburst inside of them.
It's hard to get a good photo that really shows the fire.
I believe this is also called a "Quantum" cut.
 
Last edited:
I loved Richard Homer's concave cuts for years and when looking for a spinel for my wedding ring, had 2 sent to me. They were very different in person than I anticipated. The light performance was awful and I purchased a native cut instead.

edited to add: I was looking for a deep pure red and concave cutting tends to create better light performance in lighter colored stones than darker ones.
 
Thanks Matata, this is part of my concern is that the stone will fall flat performance wise with a concave cut and might explain why you don't see a lot of this cutting with the vivid spinels.
 
As has been pointed out, you either love concave cutting or hate it. Also, it is very important to view the stones in person, as the performance is quite different from flat faceted stones, and that difference really doesn't come through in static photos. I personally do not care for concave or "mixed" (faceting combined with carving) myself. That is a very personal choice though. As to why you haven't seen many concave spinels specifically, I can't really say. I wouldn't think they are any more or less well-suited relative to other gems of similar refractive index.
 
I think the reason you don’t see a lot of concave stone is there are not that many people who do concave cutting. It takes specialized equipment, and also takes longer. Typically for me, a concave cut takes 1 to 3 hours additional time over a traditional flat faceted stone.
There is a smaller market for concave cuts, as many people prefer traditional cuts. I find that even more exotic flat faceted stones are harder to sell. People tend to like what they commonly see, so different is often difficult to sell, except for custom jewelers, who are looking for different.
If I cut two round stones, with the same diameter an proportions, the concave will be every so slightly less weight due to the concave facets slightly dishing out, but not enough to really be a concern.
 
John Dyer is a famed lapidary that does all sorts of unique cutting based on concave cuts. You should check out his website and gallery. At least you can get an idea of other unique and artful forms of this style on a wide variety of gems.
 
double post sorry
 
Last edited:
I once returned a dark green concave cut tourmaline. I concluded that darker stones are not suited for this cut. I imagine bright colors do better.
 
I disagree that concave cutting affects light performance as a general statement. I do agree that the light performance is very different though. I have traditional flat faceted and concave faceted stones. Both types are gorgeous but as beautiful as concave cutting is, there's this static quality to it that my eye and mind has trouble wrapping around. There are positive and negative points to both styles.
 
E5776607-ACD0-4BFE-A195-7DB6731A37AB.jpeg I think concave cutting can brighten up an average looking gem. I bought mine from a vendor at a gem show. He is a gemologist and cuts a lot of the stones he sells, but not all. He did not cut my amethyst. The stone is from Tanzania. I think it’s just one of those places that mines amethyst, but doesn't typically produce gems that you find in places known for their top quality amethysts. When I think of concave cut gems, for some reason, I think of quartz and topaz.
By the way, I’ve tried to take a decent shot of my amethyst 3 times. It is definitely not top color, but it looks better than this and I think concave cutting helped the gem immensely .
 
From the concave cut's I've seen it seems the larger the stone, the better the performance.......IMO
 
Sorry for the late response, today got away from me!

So many great thoughts here on the concave, looks like I will need to see some in person.

Chatoyancy and Lisa, your stones are beautiful and Karl that is an amazing looking topaz!
 
You must log in or register to reply here.
GET 3 FREE HCA RESULTS JOIN THE FORUM. ASK FOR HELP

Featured Topics

Jewelry Blog
PriceScope-Concierge-Ad
Find prime cuts.
Top