Costume Earrings Dark Purple Tiger Stripe on Abalone Shell Silver-tone

These are a very unique pair of earrings, they came from an estate -I believe these are abalone shell but am not sure because one side looks like it could be and definitely feels like it , but the other side which is almost a black with a purple tint stripes throws me since I have never seen that on abalone shell before, but that doesn't mean it couldn't - these are very thin and has a silver accent around the edge - Please see photos for measurements - In very nice Condition