PLAT engraved on the inside of the ring indicates that the ring is made of Platinum.
Sterling silver
it means the metal is 9kart
"OB" stands for Ostby & Barton
It means 18kt gold electroplated.
It means that the Silver was mined in Nevada
the bgg probably stands for the size of the ring
ApplicationGas scrubbing of Cl2, So2, No2,HCl De-aerationLiquid extractionNingbo T.C.I Co., ltd is mainly produce the pall ring, Tellerette, Saddle ring, etc. visit their website:www.rubbersealing.com
Love..
18 carat gold
i would say platinum
SC could be the initials of the manufacturer or jeweler who made the ring, or it could represent the metal composition of the ring (14k gold, for example). It could also be a personal inscription or symbolic meaning known only to the wearer.