Rio Grande Green Amethyst

Rio Grande Green Amethyst are beautiful green gemstones from Brazil’s Sierra do Cristal Mine. Displaying gorgeous and rare pine greens, Rio Grande Green Amethyst is prized for its exceptional quality, making it a striking addition to any jewelry box.

Hardness 7
Refractive Index 1.544 - 1.553
Relative Density 2.64 - 2.69
Enhancement Irradiated


Some of the best Green Amethyst available, Rio Grande Green Amethyst is extremely beautiful. The most coveted Green Amethyst is a happy medium, intensely colorful, but not too light nor too dark, with little or no secondary yellow or grey tints. Rio Grande Amethyst displays bright and attractive pine greens that typify this variety’s best color.

Brazil is not only home to much of the world’s Quartz gemstones, but also to some of the world’s best Quartz lapidaries – this is the secret to unlocking the beauty of Rio Grande Green Amethyst. Optimal cutting accentuates the innate beauty and inherent optical properties of Rio Grande Green Amethyst and every gem is finished eye-clean, the highest quality clarity grade for colored gemstones as determined by the world’s leading gemological laboratories, with excellent brilliance, scintillation (play of light), and an attractive shape and overall appearance.

Mostly mined in Brazil, Green Amethyst can be a confusing gem as it is traded under a variety of names. Ranging in shades of green from pastel to deep forest greens (sometimes with secondary yellow and grey tints), Green Amethyst is the green variety of Quartz. It is also known as Vermarine, Green Quartz, Lime Citrine or by its gemological name, Prasiolite (from the Greek words ‘prason’, meaning leek and ‘lithos’, meaning stone). Olive Quartz is a related color variety. Although Quartz of sufficient beauty to be set into jewelry is not available in great abundance, it is found in many geological environments, is a component of almost every rock type, and is also the most varied mineral in terms of varieties, colors and forms. The modern name Quartz is derived from the Saxon word ‘querklufterz’, meaning cross-vein-ore. Rio Grande Green Amethyst is a variety of macrocrystalline (large crystal) Quartz, a group which also includes Amethyst, Citrine, Lavender Quartz, Madagascan Rose Quartz, Tibetan Quartz, and Tiger’s Eye. Cryptocrystalline (small crystal) Quartz gemstones include Agate, Chalcedony, Jasper, and Onyx. All forms of Quartz are piezoelectric; when heated or rubbed they create an electrical charge becoming a magnet that attracts lightweight objects. Tourmaline is the only other gemstone that possesses this property.


Green Amethyst is somewhat unusual, better-known amongst collectors, and very limited in its fine qualities (i.e. superior color and cut).

Prized for its exceptional quality, Rio Grande Green Amethyst hails from the Sierra do Cristal Mine (Mountain Range of the Crystal Mine) located in Irai in Brazil’s southernmost state of Rio Grande do Sul (Large River of The South). Mined directly from host rock, Rio Grande Green Amethyst is typically found in vugs (small cavities in a rock or vein, often with a mineral lining).

The state after which this Green Amethyst is named, Rio Grande do Sul, is a major producer of Quartz gemstones. Brazil is the world’s leading Citrine producer and most production comes from Brazil’s southernmost state, Rio Grande do Sul. Ametista do Sul, a town in Rio Grande do Sul, reportedly has the earth’s largest deposit of Amethyst and is frequently described as the world capital for this gemstone.

Durability & Care

Rio Grande Green Amethyst is a durable gemstone (Mohs’ Hardness: 7) well-suited to everyday wear. Always store Rio Grande Green Amethyst carefully to avoid scuffs and scratches. Clean with gentle soap and lukewarm water, scrubbing behind the gem with a very soft toothbrush as necessary. After cleaning, pat dry with a soft towel or chamois cloth.

Map Location

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