Rough stone — Four shapes · Black tourmaline

A deep black striated with vertical grooves, with a distinctive glassy luster on fresh faces.

The stone as the earth formed it, simply freed from its matrix and cleaned. Sharp edges, irregular faces, a matte or glassy luster depending on the vein.

In tradition. The most classic of protective stones: tradition credits it with filtering and absorbing, particularly near workspaces.

The piece. Four shapes · Black tourmaline.

Use & upkeep. Set it on a tray, in a bowl, next to a candle. Rough pieces sit well beside polished ones, by contrast. Rinse under clear water and dry; some soft materials cannot take water, check first.

• Also called schorl, it is piezoelectric — it takes on a static charge when heated or compressed.
• A natural piece: shade, veining and dimensions vary from one example to the next

A decorative object for personal practice. It is no substitute for medical advice or treatment.