New vintage silver Pharoah Sarcophagus mask head pendant charm necklace Montréal

New vintage silver Pharoah / Sarcophagus mask head pendant charm necklace (Montréal) Special find! Egyptian symbols especially gold Nefertiti heads were very popular in the 1970s! 18x12 mm x5 deep Pharoah / Sarcophagus mask. Detailed cast. Heavy! Nice patina contrasting. Can’t find a hallmark! But I took lots of pictures! I believe it’s silver! 16” fine silver box chain, almost 1 mm wide Hallmark on chain: “GDR” + “STG” New vintage c. 1970s. I thought GDR: meant German Democratic Republic or East Germany (c. Post-WWII - 1990 unification). But it is from a Montreal jeweller who came once a year with beautiful gold and silver.