How to Spot Authentic Alexandrite vs. Synthetic Alexandrite

Alexandrite, known as “emerald by day, ruby by night,” is one of the rarest and most coveted gemstones in the world. Its mesmerizing color-changing ability—from vibrant green in daylight to rich red under incandescent light—makes it a favorite among collectors and jewelry enthusiasts. However, the market is flooded with synthetic and imitation alexandrites, making it crucial to know how to distinguish the real from the fake. In this guide, we’ll walk you through the key factors to spot authentic natural alexandrite versus synthetic gems, ensuring you invest in a genuine piece of this extraordinary gemstone.

Why Authenticity Matters

Natural alexandrite is exceptionally rare, with major mines in Russia depleted and limited production from Brazil, Sri Lanka, Africa, and India. This scarcity drives its high value, often exceeding $50,000 per carat and above for top-quality stones. Synthetic alexandrites, while visually similar, lack the rarity and investment potential of natural stones. Buying authentic alexandrite ensures you’re getting a piece of nature’s magic, backed by verifiable quality.

1. Check for Color-Change Properties

The hallmark of alexandrite is its distinct color shift:

• Natural Alexandrite: Displays a change from bluish-green or teal in daylight (or fluorescent light) to purplish-red or reddish-purple under incandescent light. The transition is often vivid and noticeable, even to the untrained eye.
• Synthetic Alexandrite: Often shows a less pronounced color change, such as green to grayish-purple or brownish hues. Some synthetics may appear too perfect or lack the subtle nuances of natural stones.
• Imitations: Gems like color-change garnet or sapphire may mimic alexandrite but typically show weaker or different color shifts (e.g., green to brown).

Tip: Test the gem under both daylight and a warm light bulb. If the color change is subtle or inconsistent, it’s likely synthetic or an imitation.

2. Request a Certificate

A reputable seller will provide a gemological certificate from a trusted lab like the Gemological Institute of America (GIA). This document verifies:

• The gem’s natural origin.
• Its color-change properties.
• Any treatments or enhancements.
• Synthetic Warning: Synthetic alexandrites (e.g., lab-grown via flux or Czochralski methods) are often labeled as such on certificates. If a seller claims a stone is natural but lacks certification, proceed with caution.
• Imitation Red Flag: Common imitations like cubic zirconia or glass won’t come with a GIA certificate.

Tip: Always verify the certificate’s authenticity by checking the report number on the laboratory’s online database. Our collection of Alexandrites includes GIA-certified natural alexandrite, ensuring transparency and trust.

3. Examine Clarity and Inclusions

Natural alexandrite often contains unique inclusions—tiny imperfections formed during its creation deep within the Earth:

• Natural Alexandrite: May show needle-like inclusions, gas bubbles, or multi-phase inclusions visible under a jeweler’s loupe (10x magnification). These are signs of natural formation.
  
  Growth lines or striations that form as the crystal grows especially from mines in Sri Lanka,Brazil, and or Madagascar)
  
  
  
  
• Synthetic Alexandrite: Typically appears too clean or shows curved growth patterns and bubbles, indicative of lab creation.
  
  
  
• Imitations: Materials like glass or low-grade synthetics may have unnatural swirls or large, irregular bubbles.

Tip: Ask a jeweler to inspect the stone under magnification. Be wary of stones that look flawless without certification, as they’re often synthetic.

4. Assess the Price

Price is a strong indicator of authenticity:

• Natural Alexandrite: High-quality stones start at $3,000 per carat and can exceed $50,000 for exceptional pieces. Even smaller stones (under 1 carat) are costly due to rarity.
• Synthetic Alexandrite: Lab-grown versions are significantly cheaper, often costing $50–$500 per carat.
• Imitations: Materials like color-change cubic zirconia or glass are dirt cheap, typically under $50 per stone.

Tip: If a deal seems too good to be true, it probably is. Authentic alexandrite’s rarity commands a premium, reflecting its value as a collector’s gem.

5. Understand the Source

Knowing where the alexandrite comes from adds credibility:

• Natural Alexandrite: Historically mined in Russia’s Ural Mountains, with modern sources in Brazil, Sri Lanka, Tanzania, Madagascar, Zambia and India. Each region produces slightly different hues, but all are rare.
• Synthetic Alexandrite: Created in labs worldwide, often in China or Russia, using methods like flux growth or hydrothermal synthesis.
• Imitations: Often mass-produced in factories with no geological origin.

6. Test with Professional Tools

For advanced verification, consult a gemologist who can use specialized equipment:

• Spectroscopy: Natural alexandrite shows distinct absorption lines due to chromium, which synthetics may mimic but with subtle differences.
• Refractive Index: Natural alexandrite has a refractive index of 1.746–1.755, while synthetics like corundum-based fakes differ slightly.
• Chelsea Filter: Under a Chelsea filter, natural alexandrite appears red due to chromium, while some synthetics may not.

Tip: If you’re investing in a high-value piece, have it appraised by a certified gemologist to confirm its authenticity.

Common Red Flags to Avoid

• No Certification: Any seller offering “natural” alexandrite without a GIA or similar certificate is suspect.
• Unrealistic Prices: Bargain-basement prices signal synthetic or imitation stones.
• Vague Descriptions: Listings that avoid terms like “natural” or “GIA-certified” may be hiding something.
• Overly Perfect Stones: Lab-grown synthetics often lack the natural imperfections of genuine alexandrite.
  
  

Why Choose Natural Alexandrite?

Authentic alexandrite is more than a gemstone—it’s a piece of history, a marvel of nature, and a smart investment. Its rarity and color-changing magic make it a standout choice for jewelry, whether you’re buying a ring, necklace, or earrings. By choosing  natural alexandrite, you’re investing in a gem that’s as unique as you are.

Ready to own a piece of this extraordinary gem?

Explore our collection of natural alexandrite 18k jewelry,  crafted with passion and precision. Browse our collection of natural Alexandrite in 18k gold, crafted in Bangkok and shipped worldwide with full certification and lifetime guarantee.