Lab or natural Alexandrite?

[recyclegold]

Hi. I was gifted a ring from 1972. The ring is 18k yellow gold, gemstone strong green blue / red CC, UV strong red. CC similar to Alex from Brazil. Was lab made Alex common in the 70s? I used spectroscope in artificial light, line 460-480 nm but no other line. Can only see small inclusion or something. Green color can not show, look gray on camera.

THANKS!

 

[Autumn in New England]

Hello there and welcome to PS! Oh yeah, synthetic alexandrite has been around since at least the 60's. And much of what folks think is synthetic alexandrite is actually just a simulant... lab-created color-change corundum, which has been around for over a hundred years.

It seems measuring RI is going to be the best preliminary indicator. Natural alex should be between 1.746 and 1.755, and is doubly refractive.

As I typically advise, if you want to be certain, send it to a reputable lab.

 

[Bron357]

And just to really confuse you, there is actually a lab grown alexandrite as in identical for every test as natural. Same RI, same SG, just no natural inclusions.
I have some from the gem haul, very confusing to say the least as they aren’t common.
Most synthetic or lab alexandrite aren’t actually chrysoberyl but lab sapphire that has been treated to appear like Alexandrite.

 

[Daisys and Diamonds]

And just to really confuse you, there is actually a lab grown alexandrite as in identical for every test as natural. Same RI, same SG, just no natural inclusions.
I have some from the gem haul, very confusing to say the least as they aren’t common.
Most synthetic or lab alexandrite aren’t actually chrysoberyl but lab sapphire that has been treated to appear like Alexandrite.

wow
so pretty
thats the best colour change i have seen on my lap top screen

 

[lovedogs]

And just to really confuse you, there is actually a lab grown alexandrite as in identical for every test as natural. Same RI, same SG, just no natural inclusions.
I have some from the gem haul, very confusing to say the least as they aren’t common.
Most synthetic or lab alexandrite aren’t actually chrysoberyl but lab sapphire that has been treated to appear like Alexandrite.

Wait, where did you get these lab Alex and where can I get them?

 

[Bron357]

Wait, where did you get these lab Alex and where can I get them?

They were in the gem haul. Had me confused for ages. Not many gems lab or otherwise are that hue of green changing to purple in incandescent light. That’s why I put them alongside my known/ confirmed Brazilian Alexandrites in the photos. I thought colour change garnet at first. I did all the tests including refractive index, SG, polariscope and under UV. All tests indicate Alexandrite. Even the good ole Presidium gem tester told me NOT garnet, corundum or spinel. Then I did some research and found out that they do in fact make a lab chrysoberyl so I figure that’s what they are. Theres 5 totalling 25.90 carats.

 

[lovedogs]

They were in the gem haul. Had me confused for ages. Not many gems lab or otherwise are that hue of green changing to purple in incandescent light. That’s why I put them alongside my known/ confirmed Brazilian Alexandrites in the photos. I thought colour change garnet at first. I did all the tests including refractive index, SG, polariscope and under UV. All tests indicate Alexandrite. Even the good ole Presidium gem tester told me NOT garnet, corundum or spinel. Then I did some research and found out that they do in fact make a lab chrysoberyl so I figure that’s what they are. Theres 5 totalling 25.90 carats.

That's so cool! I can't for tje life of me find lab alexandrite with the "right" color change