Black cathedral tourmaline in raw quality (1000gr pack)Approximate length of pieces: 4-11 cm Quality: AA Approximate diameter: 2-6 cmQuantity of pieces in the pack: 3-7 units The length and diameter of the pieces are not identical, which can affect the quantity to make a kg. In general, we make a mixture of small, medium and large pieces to reach the weight of a kilo, everything depends on the available stock.Protects against radio waves (high voltage lines, computer screens), creates a protective field around the person who possesses it and keeps evil spirits away, it gives us wisdom and intuition in addition to relaxing the nervous system while helping us to concentrate.