Antique cushion fire & brilliance

[hellokitty6782]

The H&A fire thread got me thinking and I didn't want to hijack the thread with my questions:

1) what elements of a diamond cut contribute to fire?
2) is there a combination of features that an antique or chunky cushion would have to produce the most fire (I know AVC's are specifically cut for light performance, so perhaps someone with an AVC can give us their numbers?)
3) what elements of a diamond cut contribute to white light return, and is there a combination of numbers that one would look for to get more white light return?
4) Which lighting conditions produce which visible results in stones? Should I go in broad daylight to see the fire in my stone, or would that show off the white light more?

Thanks to anyone that can help me answer these questions!

 

[antelope1]

<small bump>

I think the reason why you haven't had any replies yet it that there are no hard and fast rules for cushions, which makes buying cushions online (or in B&M for that matter) extra exciting!

In general, indirect lighting should show off the white light the most -- but this is true for most diamonds. Look for any areas that don't "close up" (and become white) when you have the diamond under the counter (this is bad).

Strong sunlight will show the fire, and also whatever leakage there is. Try cupping the diamond between two fingers (with the holder sticking through to your palm side) and if you can see your skin tone, then it's leaking -- most rectangular cushions leak a little, FWIW.

LED spotlights in a darkened room will show the color (e.g., like I-J color and lower) the most. If it leaks a lot and has a low color, you're going to see that under the LEDs.

 

[hellokitty6782]

Thanks antelope! I've actually already purchased my stone, so I'm just asking for educational purposes. I'm waiting for it to be set, but I can't wait to spend more time with it and examine it lots more once I get my ring.

 

[hellokitty6782]

By the way, are there other types of lighting, besides strong sunlight that will show the fire in a stone? I think I read that cushions are more likely to have fire rather than white light return, which is fine by me because I love the colored light.

 

[antelope1]

LED spotlight. To get fire, look for broad spectrum light from a directional light source.

 

[LGK]

Places like Costco, and Home Depot and other big box stores usually have lighting that really makes diamonds show lots of fire- and makes them very, very white.

Upscale restaurants with small bright halogen spotlighting but that are otherwise dim, also are fabulous for fire in diamonds. Elevators often have this type of lighting too. That type of light usually makes diamonds a bit dark in body color (no matter what the actual color of the stone) but with intense, intense fire flashes. The closer to ideal cut, the darker the diamodn appears actually. Sunlight also shows this phenomenon, which I believe Karl K in his strmrdr incarnation explained in much detail... I think it has to do with our pupils constricting because the diamond is just too bright to actually look at, which leaves a dark grey appearance but with intense bright fire.

Oh, and christmas tree lights too. Also very fun.

And on a sunny day in the summer, find a tree with a bit of sun coming through the leaves, and a little wind. That's one of the absolute *best* types of light to appreciate fire in your diamond. (I have a favorite bench I sit on under a tree during my lunch breaks in the summer; I spend an embarrasing amount of time appreciating my jewelry there, lol.)

ETA, again: Antique cushions, and other diamonds with chunky facets, small tables and high crowns, like OECs, do seem balanced more towards fire than white light to me, which I also prefer. I finally got to compare a squarish AVC with a really good ASET to my well-cut OECs, and it was pretty interesting. The OECs- even one with almost the exact same mm face up size as the AVC- had larger chunkier facets overall, which return a *lot* of fire. The AVC has the large facets under the table, but smaller facets around the edges, so more of a variety of facet size- so the really eye-catching fire on the AVC are the maltese cross facets under the table. The result is, the OECs looked a little bit *brighter*- more white light return- but about equal in fire. The the maltese cross under the table in teh AVC really is a knockout, though, and when those facets flash "on", the fire is awesome. IMO the cushion and the OECs were pretty close in fire return but the OEC was a bit better in terms of brilliance. Which surprised me a little actually.