Verneuil Sapphire
What is Verneuil Sapphire
The Verneuil sapphire is a synthetic sapphire created using the innovative Verneuil method (also called flame-fusion). Chemically identical to natural sapphire (Al₂O₃), it combines exceptional durability, optical clarity, and customizable color. Thanks to its efficiency and affordability, it has become a key material for both industrial and luxury applications.
Technical informations
| Growth Process | |
|---|---|
| Flame fusion melting | |
| Boules are typically small (<100mm) | |
| Chemical Composition | |
| Minimum 99.99% Al2O3 (Aluminum oxide) | |
| Verneuil Sapphire is chemically identical to natural Sapphire, consisting of pure aluminum oxide with minimal impurities | |
| Physical Properties | |
| Crystal structure | Hexagonal rhombohedral single crystal |
| Hardness | 9 on the Mohs scale, only second to diamond |
| Density | Approximately 3.99 g/cm³ |
| Optical Properties | |
| Clarity | Often has fewer inclusions compared to natural Sapphire, but can have curved striae (growth lines) that are characteristic of the Verneuil process |
| Refractive Index | 1.762 – 1.770 |
| Birefringence | 0.008 – 0.011 |
| Fluorescence | May fluoresce under ultraviolet light, depending on the impurities |
| Transmission range | 0.15 to 5.5 micron (from UV to mid-IR) |
| Mechanical Properties | |
| Comparison | Similar to Kyropoulos, although less expensive |
| Annealing | Annealing is necessary to reduce internal stress |
| Thermal Properties | |
| Melting Point | Around 2,050°C |
| Thermal Conductivity | 0.15 to 5.5 micron (from UV to mid-IR) |
| Market Value | |
| Verneuil is faster and more affordable than other sapphire growth methods | |
| Allows color variation adding dopant elements | |
Verneuil Sapphire applications
Industrial Applications
Verneuil Sapphire is used in various industrial applications, including watch faces, scientific instruments, and semiconductors, due to its hardness and thermal stability.
Jewelry
Verneuil Sapphire is often used as a gemstone in rings, necklaces, and other jewelry due to its durability and variety of colors.
The Verneuil method: how it works
Developed by Auguste Verneuil in 1902, the Verneuil method was the first commercially viable way to grow synthetic sapphire. It marked a turning point in materials science, making sapphire accessible beyond rare natural sources.
The process begins with ultra-pure alumina powder, melted in an oxy-hydrogen flame. As it cools, the material crystallizes into a single-crystal “boule.” This Verneuil sapphire is rated 9 on the Mohs scale for hardness and is virtually indistinguishable from natural sapphire, except for its controlled growth lines.
FAQ
Want more information about our Verneuil sapphire? We can also design a custom solution tailored to your application.
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