Amphibole or Caramel Amphibole — Rolled

Caramel Amphibole is a variety of the amphibole group, double-chain silicates with the general formula (Ca,Na,K)₂₋₃(Mg,Fe,Al)₅(Al,Si)₈O₂₂(OH,F)₂, whose caramel to golden-brown color results from the specific proportion of iron (Fe²⁺) and magnesium in the crystalline structure, with a predominance of varieties such as actinolite or iron tremolite. It forms in medium-grade metamorphic rocks and in zones of hydrothermal alteration of mafic and ultramafic rocks. The characteristic caramel shade is distinguished from the darker varieties of the group by the lower concentration of total iron and higher proportion of magnesium in the structure, resulting in lighter and warmer pigmentation. It presents prismatic cleavage in two planes with an angle of approximately 120°, a diagnostic property of the group. The mechanical rolling process progressively rounds the ends and corners of the parts, resulting in a smoothed external profile. Hardness: 5 to 6 on the Mohs scale. Density: 2.9 to 3.3 g/cm³. Crystalline system: monoclinic to orthorhombic. Available variations, approximate data: Size: 2 to 6 cm Unit weight: up to 100 g (approx.) Average: 13 to 25 pieces per kg (approx.)