This is a Saturday icon. We've made it in iOS style, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 12,300 icons, all in the same style and quality.
The image is a square with two little tabs at the top. It looks like the page of a calendar. There are two letters on the image. In the center of the large square part is a the capital letter S and the lowercase letter a.