Color me emerald by day, ruby by black light

[Ctwmn]

What do we have here? I've heard different things. I'm a small-towner, don't know exactly to do. Do you? Marlow?

 

[qubitasaurus]

Do you know, I think you have the wrong forum. (Try the other gemology forum). Either that or you are addressing a current user by a name they used years ago but do not use on PS at the moment.

Why the question? It is a bit of a strange one. Especially with no pictures and addressed at a PSer who chose to delete their account years ago due to being fed up with trolling. It kind of feels like you started out on the other forum, and then came here (but then chances are good that you already know the answer to your question, and that it is currently underdefined as a proposition.).

 

[Bron357]

Daylight green colour can be any number of gems, emerald, garnet sapphire, green amethyst (Prasiolite) tourmaline, Alexandrite. The gem could also be a lab grown variety (ie spinel and corundum).
Black light UV detects chromium, it is not a diagnostic test as such because even with gem groups some might fluoresce other not. Many lab grown gems fluoresce under UV.
Checking specific gravity will help identify gemstone variety but not between natural and lab grown material.
checking for inclusions can help, a perfect looking gemstone under moderate magnification is usually lab grown material.
Alexandrite glows a sort of orange colour under Black Light, the main test for Alexandrite is the colour change between daylight (green) and incandescent light (purple/red). Lab grown Alexandrite exists and will also show this phenomenon. Again, checking for inclusions usually IDs lab grown Alexandrite. Size is also an indicated, size over 2 carats is rare in natural Alexandrite. In Natural Alexandrite, like emerald, inclusions are expected.

 

[Ctwmn]

Daylight green colour can be any number of gems, emerald, garnet sapphire, green amethyst (Prasiolite) tourmaline, Alexandrite. The gem could also be a lab grown variety (ie spinel and corundum).
Black light UV detects chromium, it is not a diagnostic test as such because even with gem groups some might fluoresce other not. Many lab grown gems fluoresce under UV.
Checking specific gravity will help identify gemstone variety but not between natural and lab grown material.
checking for inclusions can help, a perfect looking gemstone under moderate magnification is usually lab grown material.
Alexandrite glows a sort of orange colour under Black Light, the main test for Alexandrite is the colour change between daylight (green) and incandescent light (purple/red). Lab grown Alexandrite exists and will also show this phenomenon. Again, checking for inclusions usually IDs lab grown Alexandrite. Size is also an indicated, size over 2 carats is rare in natural Alexandrite. In Natural Alexandrite, like emerald, inclusions are expected.

Unfortunately it's not a gemstone it's still in the rough it's a rock. it is also very difficult to show the colors

 

[Nick_G]

Looks like a chrysoberyl to me but the pics aren't great.

The alexandrite specimen I have here with me fluoresces deep red in LW UV.

 

[Ctwmn]

Here is a better picture of the green... I'm not able to get it to photograph the red