Identify Makers Mark with "OW" and a Globe Symbol

by Jim
(Modesto, CA, US)

They appear to be antique pearls with a "925" stamp on one side of clasp & "OW" & a globe in boxes, so 3 boxes containing each letter & one symbol. Similar to this graphic I made. Then again, it could be the reverse:
"Globe + M + O" in boxes.
Any information would be greatly appreciated.
Thank You,
Jim