By way of backround, Recently cut some stunning light lavendar/pink garnet that I was given. Origin unknown. Trying to souce more I got lost in the rabbit hole of garnet ID. Thanks to kirk ferals papers i now have a framework to begin understanding of this intriguing group of minerals.
To the question… in a recent parcel of stones (sold as « umbalite »???) there is one that has a really very strong pure red colour coming through the stone (transmitted white light - gem torch and sunlight) when viewed through the thickest axis. The colour is otherwise a pink purple. They are all quite saturated stones 5-7 carats and seem to have the same hue. The one displaying the red
) is the largest and it is only seen when looking through the longest axis.Given garnet shouldn’t be dichroic could this be usambara effect? What else might explain such a really striking difference? Given i have no gemological instrumets (or real knowledgeat this stage any suggestions would be much appreciated…
Also, I am keen to further my gemmological knowledge so any suggestions as to simple equipment that I can get and learn to use?
I don’t have the stones with me but will attempt some photos later this week. I’ll try stacking and see if the effect is more pronounced.
Thanks, and shift this post to a more suitable forum if needed!
