Tumblestone - Quartz, Clear A single tumblestone measuring approximately 15mm - 25mm in size. £1.00 Quantity: at £1.00 each Add To Basket 0 in your basket View Basket Checkout The most powerful and healing energy amplifier on the planet. Absorbs, stores, releases and regulates energy. Enhances psychic ability and aids concentration. Amplifies the power of other crystals used or carried with it.