It means that it was commissioned and sold by TGGC or The Genuine Gemstone Company.
Tanzanite
What does 925 tggc on a gold ring mean
What does 55 mean on a sliver ring
925 is the silver quality and I beleive that the TGGC is a company trademark. The Genuine Gemstone Company. TGGC dot com
might be the element Cerium. not quite sure. Cerium is sliver in color
Nissan
it means spit (sliver)
It is the initial of the designer or company. What is more important is the grade of gold or sliver.
92.5 sterling sliver
Platinum ring NEVER turns black. Only sliver rings turn black.
It is acceptable for men to have gold, titanium, platinum, tungsten and even sliver on their wedding rings. It is also acceptable for men to even have gemstones and diamonds on their wedding ring.