vintage silver overlay glass trivet, unmarked sterling silver tea kettle plate

20th century vintage silver overlay trivet for the tea table - this is pierced silver on a glass plate 6" in diameter. I can't find any hallmarks or sterling marks, though these are typically sterling silver and this looks like sterling silver to me. I'm not going to scratch it up to test it!

The metal work looks very good, a little tarnished, no damage. Glass has a few small spots and scratches which I've tried to show in the photos. They're hard to see unless held just so in the light.