DIAMOND question : What are the different diamond certificates called?

I guess if I bring a diamond ring somewhere and want them to tell me how good it is and the value? What is that called, who does that type of thing, and how much does that normally cost?|||Appraisers GIA certifies Diamonds EGL does whole rings EGS IGI


for the diamond about 100 dollars depends ont he size


for the ring about 50 dollars