3.1 x 0.7 x 0.6 cm (largest). A classic and fine pair of feather-like or leaf-like, spinel-twinned copper crystals with a rich patina from the 1970s finds at the Ray Mine. The crystal structure is exquisite and they look great from all sides. Many of these were treated to bring out the shine. Fortunately, these were not. Ex. Jaime Bird Collection.