The Magic of Colour-Change Gemstones: Natural, Lab-Grown & Fakes Explained
One of nature’s most enchanting tricks is the colour-change effect found in a select group of gemstones. These gems transform before your eyes, shifting hues depending on the lighting—from warm incandescent to cool daylight. Whether natural, lab-grown, or unfortunately fake, colour-change gemstones are as fascinating as they are beautiful.
In this guide, we’ll explore:
Natural colour-change gemstones
Lab-grown alternatives
Common fakes and imitations
The rarest colour-change gem of all
🌈 What Is a Colour-Change Gemstone?
A colour-change gemstone shifts its colour depending on the light source. This optical effect—caused by how the gem’s crystal structure absorbs and reflects different wavelengths—is most noticeable under daylight (blue spectrum) and incandescent light (yellow/red spectrum).
💎 Natural Colour-Change Gemstones
1. Alexandrite (Chrysoberyl)
Change: Green/blue-green in daylight → Red/purple in incandescent light
Origin: Russia, Brazil, Sri Lanka, Tanzania
Note: The most dramatic and rare of all colour-change gems.
2. Colour-Change Garnet
Change: Olive green or yellowish in daylight → Reddish-purple or pink under incandescent
Origin: Kenya, Madagascar, Sri Lanka
Note: Often confused with alexandrite but distinct under gemological testing.
3. Colour-Change Sapphire
Change: Blue in daylight → Violet or purple in incandescent light
Origin: Sri Lanka, Madagascar, Tanzania
Note: Rare and highly collectible among sapphire lovers.
4. Colour-Change Spinel
Change: Blue or gray in daylight → Reddish or violet indoors
Origin: Sri Lanka, Vietnam
Note: An underrated gem with an elegant transition.
5. Diaspore (aka Zultanite or Csarite)
Change: Yellow-green to pinkish-champagne tones
Origin: Turkey
Note: Traded under various brand names but is always a type of diaspore.
6. Fluorite
Change: Light blue to purple
Origin: China, Mexico
Note: Beautiful but soft—better for display than jewellery.
🔬 Lab-Grown Colour-Change Gemstones
Lab-grown colour-change gems offer the magic of nature with a modern, ethical, and more affordable twist.
1. Synthetic Alexandrite
Made by: Czochralski or floating zone method
Change: Similar to natural alexandrite—green to reddish-purple
Note: Chemically close to the natural version but much more available.
2. Synthetic Sapphire & Spinel
Change: Blue to violet or pink, depending on the formula
Note: Less expensive but visually appealing options for colour-change jewellery.
3. Colour-Change Cubic Zirconia (CZ)
Change: Pink to lavender, green to brown, etc.
Note: Entirely man-made, commonly used in fashion jewellery.
🚨 Fake Colour-Change Stones: What to Watch Out For
Sadly, not all colour-change gems are what they seem. Here are some of the most common fakes and how to spot them:
1. Dyed Glass Imitations
Trick: Colour-change effect is painted or layered onto the surface.
Giveaway: Bubble inclusions, poor durability, and no actual crystal structure. Cheap costume jewellery often uses these.
2. Doublets & Triplets
Trick: A thin layer of a real gemstone is glued to coloured material.
Giveaway: Look for visible glue lines or color zoning under magnification.
3. "Alexite" or "Zandrite"
Trick: Marketed as synthetic alexandrite but often just coloured glass with a slight lighting reaction.
Giveaway: Inconsistent or unimpressive colour change. Usually very cheap.
4. Photochromic Stones
Trick: Stones that change colour when exposed to UV light, not different lighting sources.
Giveaway: They need direct sunlight or UV to change, not indoor light.
5. Cheap CZ Fakes
Trick: Sold as “alexandrite” but are just coated cubic zirconia with a mild tint.
Giveaway: No gem lab certification, often under $20.
✅ Tip for Buyers: Always ask for gemological certification when buying colour-change stones—especially if it's sold as "alexandrite". Trusted sellers will be transparent.
👑 The Rarest of Them All: Natural Alexandrite
Hands down, natural alexandrite is the most rare and valuable colour-change gemstone in the world. Top-quality specimens, especially from Russia, can fetch more per carat than diamonds. Only a few deposits exist globally, and finding stones with a strong green-red shift is increasingly rare.
Coming in second are strong colour-change garnets and sapphires, though they are far more accessible.
💬 Final Thoughts: The Allure of Colour in Motion
Whether natural, lab-grown, or just a fashionable fake, colour-change gemstones add an element of surprise and intrigue to any jewellery collection. At their best, they blend science, rarity, and art, bringing each piece to life with shifting shades.
At Nowlan Jewellery Co., we love helping clients explore the world of gems—honestly, ethically, and beautifully. If you’re curious about incorporating a colour-change stone into your next custom piece or just want to learn more, come in and chat with us anytime.