Amethyst 14K gold ring

Trigonal system, the crystal is hexagonal columnar, cylindrical with transverse grain, left shape and right shape, twin-crystal is common. Hardness 7. The crystals often contain irregular or feathered gas-liquid two-phase inclusions. Because part of Si4+ in the lattice is replaced by Fe3+, and under the influence of irradiation, the [FeO4] color center is formed, causing the crystal to appear purple [2]. It is transparent and has obvious polychromatic property when viewed under dichroic mirror.