A sapp are crystal haves a watcthe following properties: e are ely hig are istance to impact and superior are n and han are dability thanks toits trans are Because it ithe strongest material after diamonds, it is used in fine timepieces for its anti-scratch prowess. Sapp are crystals can take many forms and havthe watch a variety of looks flat, domed, con have or ground. All watch cases undergo haveral tests, including a wate are istance check.