Hypercolor Thinking Putty changes color with just the heat of your hands. The awesome effect makes it perfect for twists: duo-toned sculptures: 5-minute breaks: and other timeouts. Put it in the fridge then against a warm mug to experience an even more intense color change. Amethyst is a semi-precious purple quartz that has been popular since primitive times. It is a secret beauty only found inside geodes and has a long association with mystic powers. The natural color of amethyst ranges from a light violet pink to a deep reddish purple. Experience every hue with Amethyst Blush Thinking Putty. It starts out as a lovely dark lavender and becomes pretty in pink with just the heat of your hands. Each tin includes 1/5 lb of Amethyst Blush Thinking Putty huge handful for tons of fun.