Sleepiness, haziness, and extinction questions...

[Gempassion]

Hello it's me again,

I was just wondering how you expert pricescopers can tell that a stone is sleepy? Take this Strawberry Pink-Red spinel from Gemfix for example (top right corner of the page):

http://www.gemfix.com/spinel.html

It is a vvs stone, which is characterized with "slight haziness" (which I take to mean that it would be a sleepy stone). But, I thought that vvs stones were by definition clear and therefore less sleepy than, say, a vs. Or, does sleepiness have nothing to do with clarity?

Also, do sleepy stones become extinct under low lighting conditions?

I hope my questions make sense...

 

[T L]

I don't think a sleepy stone should be graded with VVS clarity, especially one that sleepy. However, to be honest, I'm not sure if the minute inclusions making the apparent haziness in the gem would be considered "eye visible." Perhaps a gemologist can comment on this. I never thought of that question, but it's a good one.

As for your second question, I think it depends on the tone. Very dark stones tend to go extinct under low lighting, as well as other lighting conditions (even sunlight can cause extinction in some gem material). However, sleepy stones, in particular ones of a medium tone and lighter, don't tend to go extinct in low lighting conditions in my experience with them. There could be exceptions. My sleepy spinel does not go extinct, and it's a medium tone.

 

[ValentinesJewelryDesign]

Colored stones are divided by Types 1 2 and 3. Type 1 stones are Topaz, Ctirine, Amethyst etc that are readily available and easy to find with no eye visibles. Type 2 stones are Ruby, Sapphire, Spinel, etc....stones that can be found clean but often have faint eye visibles even i stones that are considered clean. Type 3 is Emerald, Alexandrite, etc....in which even the cleanest of stones will have eye visible inclusions. In Type 1 stones, slight haziness would not get VVS but in this case Spinel is a Type 2 and in all likelihood, the picture made the haziness worse. In my opinion, VVS is probably an accurate grade but it's tough without the stone in hand. I hope this helps!

Matt

 

[Gempassion]

Thank you both for clearing that up for me!

 

[chrono]

I believe depending on the amount of silk and the category it falls under, a stone can be considered either VS or lower/higher. In this case where I don’t think the silk is overpowering, it could well deserve the rating as described. In some stones, a slight haze appears velvety, some will appear a touch oily and if the silk is too strong, it may appear almost translucent. Even with a medium dark tone, with a touch of silk, the stone doesn’t appear to go extinct under low light conditions because these minute inclusions peppered evenly through out the stone disperse the light back to the eye differently than its crystalline version.

 

[Gempassion]

Thank you Chrono,
That explains the vvs rating.

 

[jleb]

There's a 1.08 carat sleepy spinel floating around on the internet where you can see what we are talking about. Here's one picture.




(disclaimer: Not my stone, i have no interest in it, for educational purposes only)

 

[Gempassion]

Ah ok, thanks for that picture! I see the sleepiness.