Color Changing Gemstones
Color change gems show different colors when viewed under different light sources, such as sunlight and indoor light.
What Causes the Color Change?
Several factors can contribute to a gemstone's ability to change color:
Pleochroism: This inherent property of certain crystals causes different colors to be visible depending on the viewing angle and direction of light. For example, alexandrite can appear greenish in blue light and reddish in incandescent light.
Chromism: This refers to the ability of a material to change its color depending on the wavelength of light it absorbs. In color-changing gemstones, specific ions within the crystal structure selectively absorb different wavelengths of light under different lighting conditions, leading to the observed color shift.
Structural changes: Certain stones, like garnets, have color-changing varieties due to slight variations in their mineral composition and atomic structure. These changes can cause shifts in light absorption and, consequently, perceived color.
Common Color-Changing Gemstones
Alexandrite: Perhaps the most famous, known for its dramatic shift from green to red.
Color-change garnet: Various garnet types exhibit color changes like purple to green, blue-green to purple, and orange to pink.
Zultanite: This rare gem displays a spectacular range of colors, from cognac and champagne to kiwi green and raspberry pink.
Color-change sapphire: These sapphires can showcase shifts from blue to green or purple, depending on the lighting.
Diaspore: Csarite, a variety of diaspore, showcases a vibrant green to yellow change.
Fluorite: This gemstone comes in a wide range of colors and can display a rainbow-like play of color due to its internal structure. Some fluorites also exhibit a distinct color change between daylight and incandescent light.
Astonishingly beautiful, exotic and rare, Zultanite demands a double take - its unique color change is truly that mesmerizing. If for you fashion is all about getting attention, Zultanite is set to redefine your look.
While some of Zultanite's key characteristics are its delicate color saturation, durability and scintillation (play of light), the beauty and intrigue of this regal gemstone ultimately lies in its different colors. Zultanite displays a range of earthy hues and similar to the famous color change gem Alexandrite, it can change from kiwi greens in sunlight (candescent light) to raspberry purplish-pinks in candlelight (incandescent light).
But unlike other color change gems such as Alexandrite, Zultanite's color change is not limited to two basic colors. Incredibly, the same Zultanite can also exhibit khaki greens, sage greens, cognac pinks, pinkish champagnes, canary yellows, rich champagnes and gingers in different light sources. Zultanite's kiwi greens with canary flashes are noticeable under sunny skies, while traditional indoor lighting will elicit rich champagne colors.
During a candle lit dinner, the same gem reveals pink to raspberry hues. While just wearing Zultanite unveils its breathtakingly diverse colors, one of its most unique characteristics is that unlike other color changes gems, Zultanite's best color change is not dependant on dark tones.
According to the leading gemstone author Antoinette Matlins, some women prefer the colors of Zultanite because they like the more subtle pastel contrast and find they complement earth tones (green, chocolate, mocha and gold), making the gem more wearable. Like all color change gemstones, the larger the Zultanite, the more visible the color change.
As if one phenomena wasn't enough, some Zultanite also possess the coveted cat's eye effect. Chatoyancy or the cat's eye effect is a reflection effect that appears as a single bright band of light across the surface of a gemstone. It is caused by the reflection of light by parallel inclusions.
The GIA (Gemological Institute of America) classifies Zultanite as a Type II transparent gemstone, meaning that it is usually eye-clean (no visible inclusions when the gem is examined approximately 6 inches from the naked eye) with some inclusions visible under 10x magnification.
Inclusions are tiny natural features that grow within the crystal during a gem's formation within the earth. Mostly microscopic in nature, inclusions are a fascinating hallmark of authenticity, recording a gem's natural relationship with the earth. They are also extremely useful to gemologists when identifying natural gemstones from synthetics and imitations.
Zultanite registers 7 out of 10 on the Mohs' Hardness Scale (a system devised in the 18th century by a Viennese mineralogist Friedrich Mohs to measure the ability of a gem to resist surface scratching), has a refractive index of 1.75 and specific gravity of 3.39.
Unless you're a gemologist, these numbers won't mean much to you, but these characteristics make Zultanite an excellent jewelry gemstone. As 100% natural gemstone, Zultanite is one of the few gems that have no known enhancements or treatments.
While the newness of Zultanite means that it has had little time to accumulate legends and lore, for those interested in the esoteric properties attributed to gemstones, some people believe Zultanite can assist in the development of psychic power, astral force, ambition, intellect, desire and emotions based on intellect and touch.
The alexandrite variety displays a color change (alexandrite effect) dependent upon the nature of ambient lighting. Alexandrite effect is the phenomenon of an observed color change from greenish to reddish with a change in source illumination.
Alexandrite results from small scale replacement of aluminium by chromium ions in the crystal structure, which causes intense absorption of light over a narrow range of wavelengths in the yellow region (580 nm) of the visible light spectrum.
