I found this link that may be helpful to some new detectorists as to their jewelry finds. Since we as beach and u/w detectorists seem to find the lions share of jewelry in the MD hobby, it pays to have at least a general working knowledge of grading and identifying gemstones, as well as marks on gold, silver, plat, etc. http://www.ftc.gov/bcp/conline/pubs/products/jewelry.htm
Hope this helps.
Hope this helps.