Multi Semi Precious Stone Intarsia Box Mounted Sterling Silver 925 Model of Frogs. This beautiful present box is fabricated of Black Onyx and inlaid with different minerals such as: Lapis-lazuli, Picture Jasper, Rhodochrosite Cabochon, Citron Magnesite (Lemon Chrysoprase), Bamboo Jasper Slab and Mother Of Pearl. 925 Sterling Silver Stamp and Initial O.S Underneath One Of The Frogs. Intarsia traces its history back to Italy and the Renaissance where it is called Pietra dura or pietre dure. This is a term for the inlay technique of using thinly cut and polished stones to create images. ... Intarsia items are generally crafted on green, white or black base stones. 3.5" x 2.5" x 0.87"