gemology, opal is a captivating, hydrated amorphous form of silica and the traditional birthstone for october, vintage illustration - 矽石 幅插畫檔、美工圖案、卡通及圖標
minerals and their crystalline forms engraving antique illustration, published 1851 - 矽石 幅插畫檔、美工圖案、卡通及圖標雕刻圖像, 藍寶石, 化學
minerals and their crystalline forms engraving antique illustration, published 1851 - 矽石 幅插畫檔、美工圖案、卡通及圖標圖畫 - 藝術品, 石英