Lab-grown rubies continue to experience several advances that improve its carat weights, internal structures, and other essential features. For example, a recent cushion-cut synthetic ruby recorded a high 14.5-carat weight with several features similar to earth-mined rubies.
Many markets adopted lab-grown rubies in the 1990s when it was clear these stones have proper features required to serve as jewelry pieces, loose gemstones, and much more.
In this article, we’ll be looking at lab-grown rubies’ history, maintenance tips, uses, and so much more.
History of Lab-Grown Rubies
Synthetic rubies penetrated jewelry markets around the 1960s to offer designers, jewelers, and artisans more options to serve growing demand for precious stones. Many of the first lab-grown rubies formed through hydrothermal processes before other methods like floating zone and pulling became popular.
How are Lab-Grown Rubies Made?
The hydrothermal method involves these steps:
- Raw elements to produce rubies are placed in an airtight environment,
- Corundum seed plates are suspended at the growth chamber while nutrients are placed underneath,
- The chamber is heated up to between 400C and 600°C.,
- Pressure on elements in the container stands between 5,000 psi and 30,000 psi,
- Nutrients dissolve to form a solution that deposits fresh corundum growth over the seed crystal.
The size of resulting rubies depend on how large the seed crystal and growth nutrients are. Time also plays a role in determining the size of synthetic rubies grown through hydrothermal processes.
Pulled Czochralski method
The pulled Czochralski method forms rubies during a special process initiated by aluminum oxide. The process involves these steps:
- Aluminum oxide (Al2O3) melts in a special container through contact with special radio waves,
- Dip a rod tipped with ruby element and growth nutrient into the aluminum oxide mixture,
- Slowly rotate and pull the rod out to form a ‘pulled’ column of ruby
Pulled crystals made with this method are usually superior to many other lab-made ruby versions.
Flame fusion method
Rubies form through the flame fusion method. This method involves:
- Dropping particles of aluminum oxide and others like chromium oxide through a heated oxy-hydrogen flame,
- Molten particles of heated elements collect at the base of the hydrogen flame to form synthetic rubies
Later flame fusion synthesis also involves mixing pure aluminum oxide and chromium oxide in a controlled environment with a stream of oxygen and a heated gas flame.
Uses of Lab-Grown Rubies
Most lab-grown rubies are useful as:
- Loose gemstones,
- Centerpieces on jewelry,
- Detailing on luxury art, and
- Adornments on musical instruments, jewelry, art pieces, etc.
Rubies are easy to work with and provide designers with enough support to create beautiful pieces for various needs.
Chemical Properties of Lab-Grown Rubies
- Chemical Formula: Al2O3
- Fracture: Conchoidal
- Hardness (Mohs’ Scale): 9
- Heat Resistance: 250°C to 340°C
- Luster: Vitreous
- Refractive Index: 1.76 – 1.77
- Specific Gravity: 1.69 g/cm3
Maintenance Tips for Lab-Grown Rubies
Blue ruby gems need maintenance to preserve their brilliance, and overall appeal. How you maintain rubies depends on their mount material, setting, intended use, and other essential factors.
You can maintain your gemstones with these methods:
- Storing in an airtight, cushioned, and humidity-free container, and
- Soaking in a vinegar and baking soda solution for 10mins
- Polishing with a dry cloth,
- Cleaning with loosely-concentrated soap solution, rinsing, and allowing to air dry
Consult your jeweler for the best tips to keep your rubies in top shape. Some rubies might react badly to harsh chemicals in some commercial cleaners.