This is a Night Landscape 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 12,800 icons, all in the same style and quality.
This icon contains two triangles representing mountains. The left triangle is slightly larger and overlaps the one on the right. Above the right triangle there is a crescent moon shape, with the crescent being on the right side.