I am so happy with this piece. It's very striking and truly one of a kind! The other name for this stone is Porphryl, which is a limestone matrix with Andalusite crystals. The pendant itself measures 2 1/4" long and 1 1/2" wide. The actual stone is 40 mm x 30 mm. It hangs from a 21" sterling oval link chain, and the chain is embellished with flat ebony beads that are inlaid with tiny ovals of mother of pearl. There is also a 5 x 8 mm oval mother of pearl cabochon on the pendant.