Amethyst with goethite
The goethite is an iron hydroxide and become magnetic after heated ( is a special feature that occur only in this iron oxide)
Here we can see some nice tufts random oriented into the crystals with yellow-brownish color.
The gem is cut with truncated pavilion and almost flat table. From Brazil.
Size: 20.8x16.5x9.2 mm.
Weight: 21.96 ct.