I am new here and I need some help please. I found a piece of hazel atlas sea glass from the Chesapeake Bay. It looks to be the bottom of a jar and to me it seems as if it was melted. It has the Hazel Atlas mark and under that is 6738 and under that it has F 13. I have other HA pieces but I dont know how to read the numbers on the bottom. ANY help would be greatly appreciated. Thank you.