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 ovals that fit into the shape of the cabochon! These rings are darker like irises. Moving the ring, see Pearlescent colours: mostly aqua green and blue, chartreuse, and hints of 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.