This is a Landscape Filled 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 shows two triangles. One is partially smaller and slightly smaller because it is a bit hidden behind the larger one on the left. At the top of the smaller triangle is a 8 pointed star shape with a circle at it's center.