These jewelry-grade fossil teeth come from Hemipristis, an extinct species of snaggletooth shark. They have been found in Miocene Epoch Florida riverbeds and beaches. The current in riverbeds exposes fossil teeth to different minerals, like manganese and iron oxides, which stain the teeth and give them their various colors. Mineralization also makes these teeth harder and stronger than phosphate teeth.
The size, shape and color of each tooth will vary, but your item will resemble the pictured examples.