Black Obsidian - Powerful protection stone. Cleanses your aura of disharmony, negative attachments and old patterns. Safe Material - 18/8 (304) food grade stainless steel + 100% natural crystal. The straw unscrews into two pieces for cleaning. Cleaning brush included. Dimension - Straw length: 7.9". Crystal size: Length about 1.65”-1.7”(42-43mm)/ Width about 0.98”(25mm). Please note that crystals are natural, each stone may vary slightly with shape, size, color and transparency, each crystal is different and unique.