Terahertz Stone Beads Strands, Faceted, Round, Size: about 2mm diameter, hole: 0.5mm; about 179pcs/Strand, 14.96 inch(38cm).Terahertz is a man-made gemstone that is invented by Japanese scientists in order to protect the body against electromagnetic smog and?harmful radiation. What's more, it's an artificial stone called silicon, but terahertz stone has stronger prowess.