14k or 18k black stone timascus, gold lined
Seen here at 9mm wide also available in 6-8mm (please indicate in the notes while checking out) Available in either 14 or 18k, white yellow gold. This technique is what I call "stone finish" made of Zirconium and titanium. This one has a large portion as zirconium vs titanium.
14/18k Gold lined / zirconium titanium