This is a Sand Timer 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 12,900 icons, all in the same style and quality.
The icon is a simplified, two-dimensional hourglass with all of its sand in the bottom chamber. Rectangles each form the bases of the icon, which are connected by a thin shaft of glass that tapers harshly at the middle. The section below the waist contains all of the sand.