Takeda has been collecting natural stones and selling them for 25 years. This Nakayama Maruka is from a mine that was exhausted decades ago and there are no more currently being mined. This stone is an excellent polishing stone and leaves a beautiful hazy finish. The stone weighs 1 pound 14 ounces and the dimensions are about 8" x 3" x 1". We only get about 1 or 2 a year of the Nakayamas and this is an excellent example.