Neat find.
Although popularly referred to as ‘tree of life’ pendants, I don’t think that’s actually what it is in a true sense. The tree of life isn’t usually depicted as a cedar tree, although it is referred to as “Grandmother Cedar” in a few cultures.
That’s a cedar of Lebanon (Cedrus libani) which is the national emblem of Lebanon and appears on their flag. In addition, the tree is regarded as a symbol of resilience, strength, and eternal life in the Middle Eastern region, although not in the same sense as the ‘tree of life’ proper.
I believe the ‘80’ mark is for .800 fine silver and Lebanon is one of several Middle Eastern countries using that standard. For Lebanon, it’s sometimes accompanied by the word ‘LIBAN’. I don’t think it’s particularly old.
There are getting on for half a million people of Lebanese descent in America.