My great grandmother's platinum watch

Can anyone tell me when this was made or anything about it, and what it might be worth today?

It has 12 diamonds and 8 emeralds, and has a large, easy to read face measuring 17 x 27 mm. about 3/4 by 1 1/4 inches. The numbers are 18k and there is an 18k circle around the white oval face. The movement needs repair as it hasn't been used for years. It is marked platinum and 18k inside the case.On the back of the watch is engraved "Elgin USA" "15 jewels" and the number "31513161." There is also an insignia that looks like Tb and the number 4105 engraved inside the case. The watch is approximately 7 1/4 inches long. The strap is 3mm wide 2.5 thick. The watch weighs 23.8g total.

Thanks,
Tracy