It is a logo of a 3-dimensional diamond. The left sides are plan, but the upper right has dots and the bottom right has stripes.
This Geometry icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 6,000 icons, all in the same style and quality.