Mexican silver and goldstone "poison" Ring

I am very partial to ... "poison" rings and it seems that the form appealed to Mexican maestros as well. And even though they were probably not used to carry lethal substances (more like something nice-smelling to help with unsavory odors in the streets), I also love the dangerous lore that surrounds them. The sterling silver and goldstone example presented here is a classic design from the period - and it comes with its own secret. Namely that the goldstone is not a stone at all but rather a very sophisticated kind of glass. Fully adjustable thanks to its open shank, this is a ring for the daring among us...

Size / Weight: currently a sz 6 US (fully adjustable due to its open shank); face is a tad above 1" N-S and approx. 3/4" E-W; 3/4" rise; 7.1 grams

Hallmarks / Date: maker's initials "MAV" as well as "TAXCO MEXICO 925" alongside Eagle 2 assay mark; 1950s-60s

Condition: excellent vintage with a warm, yummy chocolate color in the cabs, great patina and no damage or repairs noted - the secret compartment opens and closes perfectly and stays closed with no problems

Inv# 15927