Identifying Jewelry Markings: 18K, PLAT, and a Triangle?

Question
I have a ring that is silver in color and has 1 "clear" jewel set in it. On the inside of the ring there are the markings 18K, PLAT, and another one that i cant quite see but looks a bit like 3 dots forming a triangle (however it may not be) Could you please help me identify what these mean. thank you :)

Answer
The "18Kt is 18K gold, Plat is Platinum and the 3 dots are the makers mark. I'm not familliar with this mark. There are as many of these marks as thre are jewelers and jewelry manufactures.
If you try online and published jeweler hallmark publications you may get lucky and find who makes the ring.

Sincerely,

Arthur DeMello GG (GIA)
http://www.nationalgemologicallaboratory.com