Vintage Sterling Silver & Enamel Christmas Tree Charm with Jeweled Baubles

This listing is for a vintage Sterling Silver charm. The charm is made to look like a Christmas tree with three colours of enamel work (green for the tree, red for the stand, and gold for the star on top) and jeweled baubles-- four blue and two white. I don't know what the little jewels are made of but I assume they're glass/rhinestone. This charm is in good vintage condition but does have some signs of wear on the back. Please see photos before purchasing. The charm is marked Sterling ("STER") on the back and does have a brand/maker's mark but I've been unable to make it out.