Featured Amethyst ring?

This is a ring passed down in family with other jewelry. It looks like Amethyst to me, but I know little about jewelry. I would have thought silver metal, but it doesn't have the tarnish it should have for how long it has sat unworn. There is a mark on the inside of the ring. I was hoping someone might recognize the mark. It appears to be
B | <----<<

^​

a letter B or 8 an I or bar, and a left pointing arrow with triangle underneath, unless I'm looking at it upside down. It's small and hard to photograph. I'd really like to get an idea of its age so I can narrow down which relative it likely came from. The kind of boxy setting reminds me of an antique diamond ring we have, and doesn't look like a very modern style. But what do I know? It's really dirty, and the stone (or glass) would be more appealing when cleaned. So age, likely stone, likely metal, and anything else about this ring folks can tell me is appreciated.

 

Tried again at getting a decent photo of the mark. I think this is the best I can get with the equipment at hand.

 

maybe 18 K...upside down?

 

1920s, Art Deco. White gold was popular during that period, so it could be un upside down 18k mark, like komo suggested. But do check if it is a size 8.

The mark looks like the Uncas mark, but the part in the centre of the arrow doesn't look like a U.
Uncas:

 

It's pretty and looks to have some age to it.

 

Reported, Russian spam.

 

I feel kind of stupid for not recognizing the 18 for 18k. My wife tried the ring on and she says it's a 6, so the 8 is not a size. The mark is not very legible, but between CA and Uncas, I think Uncas is the most likely. Thanks for the help. Is it more likely to be amethyst or glass? I cleaned it up some, which improved it a lot, and now have received orders that it goes into the jewelry that gets worn box.

 

Now that's a smart order !!

 

The original photos of the stone was too dirty ,take a good photo of the stone,back lite if possible.

 

So you know what to do, or else....

 

If its Uncas, odds on glass; they made a fair bit of sterling, but mostly with costume stones. If it's not theirs and sterling, all bets are off. If it were mine I'd take a gem tester to it and see what happened.

 

I am not seeing 18k because of the metal... the prongs are not right for 18k, and the wear on the metal doesn't look like gold.... I am seeing sterling that may have been rhodium plated at one time....

 

Here are some photos of the stone. After cleaning, I was surprised to see some stark color differences within stone when backlit. I thought, hmmm, it must be glass. Then I searched around and discovered zoning, although I don't know if that's what this is. I've included a bunch of photos, because how it looks depends on the angle and the light. It can all appear one color, and then change the angle a little and it's very light in one area and noticeably darker in another, and sometimes it's a very angular line between the two. I picked the angles where it shows up the most. The final picture is the ring on my pinky out in sunlight. On the finger, the color variations pretty much aren't visible. I feel like I'm beating a dead horse here since even if real, it's just an amethyst, but I'm learning a lot, so thanks for bearing with me.

 

Do you have a local jeweler that can look at it for you and test the metal and stone? I am leaning towards glass due to how scratched the stone is, but I have been wrong before.

 

Yes it has color zoning.Whoever faceted the rough stone didn't get the alignment right to flood the stone with full color.It is real amethyst.

 

Wow, I didn't know about color zoning. Thank guys!