Sapphire for watch crystals is synthetically https://www.rblunettesdesoleil.com/lunettes-de-soleil/aviator-classic-summer-capsule/ grown into a fist-sized boule that looks like frosted glass before it's cut and polished into the desired size and shape. We https://www.rblunettesdesoleil.com/lunettes-de-soleil/erika-classic-exclusive/ as customers only https://www.rboculosdesol.com/oculos-de-sol/rb3746/ see the final shape: flat, box, double-domed, and other variations. But for manufacturers, there are two basic ways to cut a sapphire crystal.