In geometry, a golden rhombus is a rhombus whose diagonals are in the golden ratio: D d = φ = 1 + 5 2 ≈ 1.618 034 {\displaystyle {D \over d}=\varphi ={{1+{\sqrt {5}}} \over 2}\approx 1.618~034} Equivalently, it is the Varignon parallelogram formed from the edge midpoints of a golden rectangle. Wikipedia