What Is Lab-Grown Sapphire?

Lab-Grown Sapphire

Sapphire is a gem that has long been admired for its beauty and durability. A precious variety of corundum—a mineral made of aluminum oxide. While natural sapphire has been used in jewelry for centuries, the advent of lab-grown sapphire technology since 1902 has created a new era for sapphire jewellery. 

Lab-grown sapphires, often indistinguishable from their natural counterparts by the naked eye, can offer a sustainable, ethical, and cost-effective alternative to mined sapphires. 

Lab-grown sapphires are created through a variety of methods. The techniques usually aim to simulate the high-pressure, high-temperature conditions found in the Earth's crust, which are responsible for forming natural sapphires over millions of years. 

Lab-Grown Sapphire Methods 

Verneuil Process (Flame Fusion)

The Verneuil process, developed in the late 19th century by French chemist Auguste Verneuil, is the oldest and most widely used method for creating synthetic sapphires. It is the cheapest & the fastest technique with material being produced in only a few hours. 

Made public in 1902 the process uses a fine powder of aluminum oxide (the raw material for sapphire) that is melted using an oxy-hydrogen flame. The molten droplets fall onto a rotating pedestal, where they crystallize to form a boule (a large, single crystal) of sapphire.

While the Verneuil process is fast, cost-effective, and can produce large quantities of sapphire, it is often limited by the quality of the sapphire it produces. Sometimes visible growth lines, gas bubbles, internal stress or imperfections are formed, however advancements in technology over time have improved the quality of these lab grown gems. 

Kyropoulos Method

The Kyropoulos method, developed in the 1970s, involves melting aluminum oxide in a crucible and allowing the molten material to cool slowly in a controlled environment. 

This slow cooling process promotes the growth of large, high-quality sapphire crystals. Crystals in very large sizes can be produced via this method. 

The Kyropoulos method allows for the production of high-purity sapphires with fewer defects compared to the Verneuil process. 

Czochralski Process

The Czochralski method is another widely used technique for growing sapphire & was introduced in 1960 for creating sapphire and is still frequently used today. 

In this process, a small seed crystal of sapphire is placed in a crucible of molten aluminum oxide, and a closely controlled environment is maintained to allow the seed to grow larger as it is slowly pulled upward, forming a cylindrical crystal.

This method is highly effective for producing very pure sapphire crystals. This quality is achieved from the precisely controlled growth rate through careful control of the power required for heating. These stones tend to sell for significantly higher prices than the flame fusion sapphires & the production process is also much more costly. 

Flux Method 

Also known as the solution growth method is a high cost, slow-growth technique where aluminium oxide is dissolved in a molten chemical solvent (flux) and cooled slowly to produce gems. Flux grown sapphires can produce natural looking inclusions which make them harder to distinguish from natural sapphires. These lab grown sapphires are the most expensive type of synthetic to produce. 

Lab-Grown Sapphire Properties

Lab-grown sapphires largely have the same chemical, physical, and optical properties as natural sapphires. 

Lab-grown sapphires share the exceptional hardness (Mohs scale 9), which contributes to their durability and suitability for regular wear in jewellery. 

Lab-grown sapphires can be engineered to achieve a specific colour or hue, making them versatile for use in jewelry and other decorative applications. The ability to control the chemical composition during the growth process also means that the color can be more consistent in lab-grown sapphires. For example, for eternity rings it is much easier to match the exact colour across all the stones for lab-grown sapphire than it is to find all matching natural sapphire. 

Additionally, lab-grown sapphires can be produced in a variety of colours, including shades that may be rarer or more vivid than those found in natural stones. 

What are the differences between lab grown sapphire & natural sapphire? 

Inclusions

Lab-grown sapphires generally exhibit excellent clarity, often with fewer inclusions or imperfections compared to natural sapphires. This makes lab-grown sapphires ideal for high-clarity gemstones. The inclusions in synthetic sapphires are typically more uniform and can be used to identify the gem as lab-created. 

Origin

Natural sapphires are formed by natural geological processes deep within the Earth's crust, while lab-grown sapphires are manufactured in a lab.

Price 

Natural sapphires are generally more expensive due to their rarity. Lab-grown sapphires are typically more affordable. 

Re-sale value 

Natural sapphires offer better resale value due to their scarcity when compared to lab-grown specimens. Natural sapphire, especially in the highest grades have consistently appreciated in value over time. This is not the case for lab-grown sapphire. 

Environmental Impact

Lab-grown sapphires tend to have a lower environmental impact, as they do not require mining, which can be disruptive to ecosystems.

Shop Lucy Jurado natural sapphire rings.