A fine-grained whetstone lubricated with oil, used for fine sharpening. The Ruby sharpening stone and Stone,For Polishing,Sharpening. Can Make Mirror surface, mirror . The Ruby Sharpening stone is made from sintered crystals of synthetic ruby. Its extremely hard, maintain their shape well and are resistant to wear. Size:50*25*10mm(1.97*0.98*0.39 inch) Model:3000 & 10,000 Grit Material:Ruby stone and natural Color: red & white(as the picture) Mainly used in industrial instrumentation, precision parts, miniature knives, stones, measuring tools, cutting tools, instruments, carbide, etc. Package included: 1x Two Sides Jade Sharpener Note:Light and different displays may cause the color of the item in the picture a little different from the real thing.The measurement allowed error is +/-1-3 cm.