Vintage Clear Quartz and Sterling Silver 925 Pendant Necklace Designer Signed

This is a vintage pendant necklace. It's a stunning, large, teardrop-shaped clear quartz gemstone set in sterling silver. It's stamped "925TM"; it's signed, but I'm unable to identify the maker. The gemstone was tested with a Presidium Gem Tester II. It measures 1.1" by 0.5" The chain is modern; it's 18" long. The necklace is in excellent condition, and it will come in a gift box.