I purchased a bunch of specimens from a collector that I used to know unfortunately he passed away his collection mostly contains specimens of tourmaline because he worked heading the digs in tourmaline mines in San Diego he volunteered for these positions just to get the specimens and he enjoyed teaching so that’s what he would do he had five gallon buckets of tourmaline when I bought his specimens they were mostly tourmaline but there was a garnet in there so this one I could use some help on I pretty sure it’s a colorless garnet Crystal knowing how much tourmaline he had (he loved tourmaline) another collector mentioned it might be a driver terminated twinned Crystal when he said it I do see these talking about so hopefully you guys can persuade me one way or the other it is heavy and it has not been polished just rinsed off and lightly brushed with a toothbrush the looks pretty amazing you can see the reflection that’s one of the reasons I’m leaning towards Garnett
It has the crystalline appearance of a felspar (or feldspar) that occurs with tourmaline in pegmatites. Colorless garnet would appear to be an oddity, as garnet is usually colored such that large pieces are not transparent. The crystal habit of garnet is also quite distinctive; and since garnet belongs to the cubic system a polariscope test on a transparent chip would definitely indicate it is a garnet and not felspar.
If you are interested in learning more about garnets, GIA has a good handy article on them.
Their gemstone encyclopedia is a great reference.
I hope this helps!
This is a grossular garnet from Morelos, Mexico