The Briar Long Sleeve T-Shirt is naturally dyed with basalt. Due to the nature of dye method variation of color is possible. Basalt is a volcanic stone that creates lightfast shades of black and grey. It is the most common rock type to cover earth’s surface. Rich in magnesium and iron, it is formed of solidified lava. The stone is often crushed for use in construction, because of it’s durability and strength. Baserange uses basalt dye extracted from quarries in Italy, France and Cyprus.