Natural Tiger Eye only comes in two colors on its own, golden brown and a blue-grey variety called Hawk's Eye, both formed when quartz slowly replaced fibrous crocidolite (a form of asbestos) while iron oxide stained the material during the process.
Black tiger eye doesn't occur that way in nature, it's produced by heat treating the golden variety until the color darkens, a standard and widely disclosed practice in the trade rather than something hidden.
That treatment doesn't diminish the stone's core feature, the chatoyancy that gives tiger eye its name stays fully intact regardless of color, since it comes from the fibrous internal structure itself, not the surface color.
Light still moves across the surface in that signature silky band as the stone turns, golden fibers now set against a deep black body instead of brown.
Each cabochon here is cut mix shape with a flat back, sourced from Madagascar, and priced by carat weight.
Black tiger eye jewelry tends to read as bolder and more graphic than the classic golden version, which is part of why it's picked up steam in statement rings and men's jewelry specifically, where the higher contrast reads well at a distance.