10K yellow gold ring with Lavendar/purple marquise cut gemstone in prong setting. 
Band is tapered. The shank has an open cut on either side of the gemstone. 
Tested using Presidium Gem Tester II and the needle pointed to  "Quartz, Amethyst, Citrine"

Size: 5 
Marked: GTR and 10K
Total Weight: 3.4 grams
Gem measurements: 14.8mm X 7 mm
Band tapers from approximately 7.9 mm to 1.8mm on the bottom of band
Condition: Pre-owned. Scratches on band from normal wear.