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Please Identify This Color-Change Gemstone


#1

Hello everyone! I am pretty new to gemstone identification and still learning. I purchased the following 2 stones in a parcel and have no idea what they are! I am pretty sure they are not Alexandrite but they are color-change gemstones. The stones are a greenish color under a fluorescent benchlight but turn a pinkish-mauve in daylight as well as candle-light. (Please see images) The Oval is 7.75 carats and the Pear is 2.77 carats.

Can anyone possibly give me any ideas as to what they might be? Thanks! :slight_smile:





#2

Hi, really impossible to make a determination on a photo of a gem with no further info, is it singly or doubly refractive?? can you get a Refractive Index of the gems or specific gravity this would lead to some more definite answers to the gems.
in saying all that I have seen some colour change garnets of similar colour??

regards.


#3

They look like they might be colour change Diaspore.
What tools do you have to help you Id them?
The stone is most likely double refractive ( Colour change)
Do you have a carat scale? so you can find the specific gravity? you can find instructions on IGS
Do you have a black light and a strong magnet? Here is a simple test you can try. Float the stones in water, if you have a piece of foam that will work well. With a strong magnet see if they are either attracted or repelled by the magnet.

If you can calculate the SG then you will help you narrow it down.
Alexandrite- SG is 3.7 3.73 - Very weakly magnetic reaction or none if it is synthetic- Should glow Red Pink under UV
Diaspore is about SG is 3.3 will react to magnetism and turn yellow / green under UV light
Colour change Garnet SG is about 3.65 , Very strong react to magnetism ( should be picked up by the magnet) but typically inert to UV light

These test are not conclusive on their own but together they can be a very good indication. They are relatively simple to do at home with very little equipment. SG may vary as will the magnetic and UV reactions but it is a good guide line.

Good Luck, have fun
Suzanne, Gemmologue.ca


#4

The top ome could also be Axanite


#5

Sure the captions aren’t reversed; i.e., outdoors is indoors? Then they look like synthetic alexandrite.


#6

Hello,

I recently bought some “Zandrite” from a TV gemstone show. They are simply glass doped with certain rare-earth metals. They exhibit a vert strong color change, and look almost exactly like your pictures. Mine aren’t worth much but are very pretty. Try putting them under cold, cool, and warm temperayure FLORESCENT light, (5000K, 4000K, 2700K). That should dramatically bring out the color change. I also have some color change fluorite that will turn forest green under one of those lights. I’ve only seen them as advertised changing from blue to purple. Different temperature LED lights have no color changing effects on the gemstones.


#7

Start with the basics … What is the Refractive Index?