Catalogue membership for Gray Crystals crosses material labels including Moonstone, Smoky Quartz, Labradorite, and Peach Moonstone and forms such as chips, spheres, tumbled stones, and carvings. The collection therefore represents a color axis: entries share the recorded color path while retaining different materials and shapes.
Begin with the recorded material choices, including Moonstone, Smoky Quartz, Labradorite, and Peach Moonstone. After that, compare the shape labels chips, spheres, tumbled stones, and carvings; both facts vary even though the entries share this color category.