Amethyst is a popular gemstone renowned for its beautiful purple color. In fact, the word “amethyst” comes from the Ancient Greek word “amethystos” meaning “not intoxicated”, as amethyst was believed to protect against drunkenness. This regal purple shade is the color most associated with amethyst gems. But can amethyst stones actually display other hues besides purple?
What Causes the Purple Color in Amethyst
The vivid purple color that amethyst is prized for is caused by trace amounts of iron within the crystal structure of the mineral quartz. More specifically, it is iron in the +3 (Fe3+) oxidation state that gives amethyst its signature color. When amethyst is exposed to heat or radiation treatments, the oxidation state of iron within the crystal changes, causing the purple color to fade or shift completely. This is why amethyst color can range from deep purple to red, pink, orange, yellow, green, brown, and even colorless.
Amethyst Color Variations
While purple is the most famous amethyst shade, this gemstone can naturally occur in a wide spectrum of other colors:
Pink Amethyst
Also known as rose de France, pink amethyst gets its delicate hue from hematite (iron oxide) impurities within the quartz. It ranges from very pale pink to deep reddish pink in tone.
Red Amethyst
Red amethyst, or ruby amethyst, contains trace amounts of hematite like pink amethyst. Its vivid reddish hue is caused by additional irradiation, which alters the iron impurities and induces a red color.
Orange Amethyst
Orange amethyst, sometimes called golden amethyst, gets its warm orangey tones from heat treatment and irradiation of the iron impurities in quartz. Natural-colored yellowish orange amethyst is very rare.
Green Amethyst
Green amethyst is created through irradiation or hydrothermal treatment of quartz, producing a light green color. Natural green amethyst is extremely uncommon.
Brown Amethyst
Brown amethyst occurs when purple amethyst is heated to high temperatures, causing the iron impurities to lose their color. It ranges from yellowish brown to chocolate brown hues.
Blue Amethyst
There is no such thing as a natural blue amethyst. However, some jewelers use color treatment to produce blue amethyst, which is actually just dyed quartz rather than true amethyst.
Other Amethyst Colors
In addition to the hues above, amethyst can also display multi-colored banding, color zoning, and backing when cut as a cabochon. The color variations arise from impurities and changes in crystal growth as the amethyst formed underground.
What Impacts Amethyst Color?
There are several key factors that influence the final color that an amethyst crystal displays:
Trace Element Impurities
As mentioned earlier, iron impurities in the form of hematite or limonite within the quartz structure are responsible for purple, red, and pink amethyst hues. Other elemental impurities can also impact color, such as nickel (green/yellow), manganese (pink), and cobalt (blue).
Heat Treatment
Heating amethyst to high temperatures alters the oxidation states and coordination of iron ions, removing purple color. The degree of heating affects the final shade, which can range from yellow to brown. Most citrine on the market is actually heat treated amethyst.
Radiation Treatment
Exposure to radiation sources like neutrons, electrons, and gamma rays causes ionization of iron ions in amethyst, producing rare colors like red and green. Jewelers must be careful not to over-irradiate or amethyst will turn dark brown.
Hydrothermal Treatment
Treating amethyst with hot water or steam under high pressure can modify iron impurities and create new colors like green. However, hydrothermal treatment is not widely used.
Geologic Conditions
The temperature, pressure, and chemical environment in which an amethyst crystal forms underground impacts which trace elements are incorporated into the structure during growth. This in turn affects the potential color range.
How Common are Non-Purple Amethyst Stones?
In nature, untreated amethyst occurs in purple more than any other color by far. True natural green, red, and orange amethyst is incredibly scarce. Here is a table summarizing the rarity levels of different amethyst hues:
| Amethyst Color | Rarity |
|---|---|
| Purple | Very Common |
| Pink | Uncommon |
| Red | Rare |
| Orange | Very Rare |
| Green | Extremely Rare |
| Brown | Uncommon |
| Blue | Does Not Exist Naturally |
However, with today’s readily available heat and radiation treatment technologies, jewelers can produce amethyst in a rainbow of colors for jewelry use. Even though treated gems are enhanced, most marketed amethyst is not natural purple. If you are looking for an exceptionally rare collector’s gem, be sure to have any non-purple amethyst verified as natural origin.
Identifying Amethyst Color Treatments
Distinguishing treated amethyst from natural stones requires expert gemological testing. Some identification tips include:
- Irradiated amethyst often shows color concentrated around fractures/inclusions where radiation penetrated more easily.
- Heated amethyst may display concentric color banding or uneven dull patches from poor heat distribution.
- With hydrothermal treatment, insert “quartz” is dissolved and deposited on the surface, showing under magnification.
- Dyed blue amethyst will have color coating the surface when examined microscopically.
- Chemical testing can identify color enhancement elements like cobalt or nickel.
- Spectrometry reveals radiation damage and increased iron in treated amethyst.
Value of Non-Purple Amethyst
In the gemstone trade, deep purple amethyst commands the highest prices, especially for larger carat sizes. Non-purple amethysts are valued based on their rarity level:
| Amethyst Color | Value |
|---|---|
| Purple | Moderate |
| Pink | Slightly Above Purple |
| Red | Premium |
| Orange | Very High |
| Green | Extremely High |
| Brown | Below Purple |
However, because nearly all green, orange, and red amethyst in the market is treated, they do not fetch the same extremely high prices that natural stones in these hues would. Blue amethyst has very little value since it does not occur naturally. In jewelry, the cut quality and carat size have more impact on amethyst’s worth than color alone.
Amethyst Color Meanings
In crystal healing traditions, different amethyst colors have unique spiritual meanings and purported health benefits:
- Purple – Wisdom, royalty, sobriety, peace, spirituality
- Pink – Unconditional love, romance, tenderness, marriage
- Red – Courage, strength, vigor, fertility
- Orange – Creativity, joy, success, abundance
- Green – Healing, balance, harmony with nature
- Brown – Stability, grounding, endurance
However, there is no scientific evidence for the metaphysical powersclaimed in crystal healing. Still, the rich symbolism and lore surrounding amethyst’s color varieties add to its aesthetic appeal.
Conclusion
While purple is by far the most famous amethyst shade, this beloved gemstone can occur in and be treated to produce a diverse spectrum of other natural and enhanced colors. These range from the pale pinks of rose de France amethyst to the fiery reds of ruby amethyst and many hues in between. However, very few amethyst stones display non-purple colors without human intervention through heat or radiation treatments. The rarity and desirability of some colored amethyst varieties like natural green make them extremely valuable collector’s items. So while amethyst is not confined only to purple, its distinctive violet hue remains the most prized color of this regal gem.
