Very Large 7.4? x 5.5? Red Abalone Shell Real Natural Polished Abalone for Decor. Pre owned. Please see pics for better detail, condition, and measurements. Abalone Shells are "bio-crystals" that come from living organisms instead of being formed in the earth's crust. They're made up of nacre (aka Mother of Pearl), which is Aragonite or Calcites crystals layered with proteins secreted by sea animals; as this shell grows it deposits many layers over time creating vibrant rainbows when light refracts through them at different angles - giving each piece an iridescent color! Native Americans have known about its healing properties for thousands upon millennia since they used these shells to adorn themselves, make tools currency but also witness rituals during sacred occasions such as celebrations where everyone feels better simply because of being able to experience some peace while out enjoying nature.