There does not appear to be any jewelry available online with the stamp of WTi. It may be that of the maker of the jewelry. The best way to find out the authenticity of a piece of jewelry is to bring it to a reputable jeweler.
No
West Texas Intermediate (WTI) crude oil is of very high quality and is at refining a larger portion of gasoline. Its API gravity is 39.6 degrees, which makes it a "light" crude oil, and it contains only about 0.24 percent of sulfur (making a "sweet" crude oil). Brent Blend is actually a combination of crude oil from fifteen different oil fields located in the North Sea. It is still a "light" crude oil, but not quite as "light" as WTI, and it contains about 0.37 percent of sulfur (making it a "sweet" crude oil, but again slightly less "sweet" than WTI). Brent blend is good for making gasoline and middle distillates. WTI is more expensive than Brent.
A maker stamp
Sai is a Jewelry brand.
the number usually helps jewelry makers keep track of each piece of jewelry she/he makes
A silversmith!
the number usually helps jewelry makers keep track of each piece of jewelry she/he makes
the number usually helps jewelry makers keep track of each piece of jewelry she/he makes
Thomas Sabo makes all kinds of jewelry including necklaces, watches, bracelets, pendants, charms, and cuff links. He makes his jewelry in sterling silver and diamonds.
the jewelry oxidizes when it gets wet. Like copper does when its outside.
The Classic Burlwood Cherry Jewelry Box by Seya Inc is one of the best