Green Opal Med-Large Freeform

706g / 1.556lbs / 24.9oz 4.40" x 3.67" x 2.31" Green Opal from Madagascar Green opal is an amorphous variety of quartz, with the chemical composition of SiO2·n (H2O) with iron-rich clay (Fe), copper (Cu), or nickel (Ni) Hardness: 5.5–6 Crystal system: amorphous Formation process: igneous or sedimentary.  This hydrated silicate mineraloid has the associated chemical composition and lack of crystal structure that terms this mineral conglomerate as an opal.  During formation, microscopic holes form within the silica, forming secondary silica lamellae-like strings throughout, giving the rock its inner web-like appearance