Identifying an Unmarked Alexandrite Pendant: Provenance and Value

Question
Can you tell me how a pendant may have been made if it is unmarked silver. I purchased a pendant from a war memorabilia store on the last day of business the owner had passed away. It was the only piece of jewelery in the store The old man wanted everything gone and very reluctantly sold me a pendant for $200. He said the stone was alexandrite although I had no clue about any sort of stones, I just found it to be perfect for me. He told me his brother would roll in his grave for selling it for so little but I thought he was a clever sales man. The pendant is about an 3/4 on inch long and oval in shape. The setting is in silver and been confirmed by a store jeweler although they could not confirm the stone. The back of the item has what looks like almost a seal on the back like a semi circle stamp? It seems like a tool was used to pull the pendant from a mold possibly? I'm unsure why would the pendant not be marked as silver? And would any jeweler have ever used an alexandrite stone with Silver? Would it not have been gold? If you have any answers for me I would be so appreciative for them.
Thank You

Answer
Hi Chantelle,
To begin with, Alexandrite is a very rare stone and therefore very expensive, I have not found any Alexandrite set in "silver" in my 30+ years in the business but it does not mean that someone did not have it set in such metal.
I will test the stone in a very simple way: take a flashlight and put the stone directly to the light for few seconds, it should change colors depending on the amount of heat it holds from the light, usually it changes to green, purple, reddish, bluish, clear at times and from different angles it can show a rainbow of colors.
If it does have that reaction then the next step should be taking it to a reputable Gemologist and have it appraised, I have to mention that also the MAN MADE ALEXANDRITES  have the same reaction to heat but in minor scale, the decision in finding out what you have in your hands is yours and it will be a little costly regardless of the authenticity of the stone.

Hope it helps,

Orlando Cajamarca
www.ocjdesigns.com