Green amethyst, a gemstone captivating with its soft green hues, often causes confusion due to its name. While commonly known as “green amethyst,” this gemstone is actually a distinct variety of quartz. Amethyst is, by definition, a purple form of quartz, making the term “green amethyst” a popular but technically imprecise label for this appealing green stone. The proper gemological name for this green quartz is prasiolite.
Understanding Green Amethyst
The gemstone commonly known as green amethyst is prasiolite, a green variety of quartz. While naturally occurring prasiolite is extremely rare, most green amethyst on the market today is produced through the heat treatment of specific types of amethyst or yellow quartz. Natural prasiolite forms under unique geological conditions where amethyst is exposed to natural radiation or heat from volcanic activity, transforming its color from purple to green. Such natural occurrences are uncommon, with notable deposits found in regions like Brazil, Poland, and Canada.
Most prasiolite available results from a controlled process where amethyst is heated to around 500°C. During this heat treatment, trace amounts of iron impurities within the quartz crystal lattice change their oxidation state. This chemical alteration causes the purple color to transform into various shades of green. This process is stable and widely accepted, making heat-treated material a common and accessible option.
Physical Properties and Characteristics
Green amethyst, or prasiolite, displays a range of green tones, from pale mint to deeper olive or forest green. Some natural specimens may exhibit yellowish or grayish undertones. The gemstone typically presents with good clarity, often transparent or translucent, allowing light to pass through. When polished, prasiolite exhibits a vitreous, or glass-like, luster.
This quartz variety possesses a Mohs hardness of 7, indicating good resistance to scratching and making it suitable for everyday wear in various jewelry settings. Its durability allows for a variety of cuts, including popular faceted designs and cabochons.
Care and Common Uses
Caring for green amethyst requires a gentle approach to maintain its color and integrity. Cleaning the gemstone with mild soapy water and a soft cloth is recommended to remove dirt and oils. Avoid harsh chemicals, ultrasonic cleaners, and steam cleaners, as these can damage the stone or cause its color to fade, particularly for heat-treated varieties. Prolonged exposure to direct sunlight should also be limited, as intense light can lead to color degradation over time.
Store green amethyst separately from harder gemstones to prevent scratches, ideally in a soft pouch or fabric-lined jewelry box. Due to its color and durability, green amethyst is widely used in various forms of jewelry. It can be found in rings, pendants, earrings, and bracelets.
Identifying Green Amethyst
Distinguishing green amethyst from other green gemstones involves observing its visual characteristics and understanding its properties. Natural prasiolite often shows a pale green color with potentially uneven distribution, while heat-treated material tends to have a more uniform and vibrant green hue. The gemstone’s Mohs hardness of 7 can be a helpful indicator, as it will resist scratching by common household items. If a stone is easily scratched, it may not be genuine green amethyst.
Green amethyst can sometimes be confused with gemstones like peridot, green tourmaline, or emerald. Peridot, an olivine mineral, differs in its chemical composition and often has a more yellowish-green tone compared to the cooler greens of prasiolite. Emeralds typically display a deeper, richer green and are often more expensive, while green tourmaline can exhibit different optical properties like pleochroism. Observing clarity and the presence of inclusions can also provide clues; natural prasiolite might have specific internal features like two-phase inclusions, whereas heat-treated stones may show “fried egg”-like cracks. For definitive identification, especially for valuable pieces, consulting a professional gemologist is the most reliable method.