New vintage silver abalone flower ring

New vintage silver abalone flower ring Simple rustic modern silver craftsmanship. Six oxidized half circles look like a flower framing the oval abalone cabochon. Oxidized BLACK finish on petals for contrast. It may not be a flower but a symbol I’m unaware of. Pretty abalone with several concentric teardrop shapes that fit into the shape of the cabochon! Darker ring like irises. Smaller center ring. Moving the ring, see Pearlescent colours: mostly aqua green and blue, and silvery grey. Simple dainty band splits into a Y-shape and welds under the oval setting. C. +1 mm high frame holding the abalone. 7x12 mm flower 3x7 mm abalone C. +1 mm band New vintage c. 1980s. Probably handmade / finished in Mexico. Genuine silver. Band Hallmark: “TR-09” (I think that’s what it says). Setting elaborate hallmark: “925”, “TAXCO”, and much that I can’t make out. Genuine abalone shell. These were black and I polished them with a little toothpaste and warm water. Group photos show others in the collection.