Natural Black Agate Cube Bead Strand (4/6/8/10/12mm)Black Agate is a variety of chalcedony, a microcrystalline quartz, known for its deep black color, sometimes with subtle banding or patterns. It is often opaque, smooth, and polished for use in jewelry, worry stones, or decorative items. With a Mohs hardness of 6. 57, it is durable and suitable for daily wear. Metaphysically, Black Agate is a grounding and protective stone, associated with the root chakra. It is believed to provide inner strength,