Beautiful Rainbow Calcite New Mexico - 3.0 oz refers to calcite that exhibits vibrant colors, which can be either a natural phenomenon caused by impurities and light refraction or a man-made material called Rainbow Calsilica that is a mixture of calcite, plastic, and dyes. Natural rainbow calcite displays a spectrum of colors from red and orange to yellow and green, often with a rainbow-like effect due to optical properties like birefringence and dispersion. # 487