Synthetic Ruby Facts
by Yuman Hussain
Synthetic ruby facts tell us about the different processes of lab- based ruby formations. It also tells about main features of some of the popular synthetic rubies available in world markets.
Ruby ‘the Lord of the Gems’ is desired for its rarity and beauty. Acquiring its name from Latin word ‘Rubeus’ it symbolize love and passion. It is the red variety of mineral corundum with colors ranging from purplish to bluish red to a yellowish red. However the finest variety of ruby has vivid red color with the faint undertone of blue as found generally in Burmese rubies. Ruby due to their sturdiness and beauty makes a fine choice for any piece of jewelry. It is an accepted birthstone for the July -born individuals.
Passion for rubies led to their mass production in the laboratories. A.V Verneuil was the first one to create synthetic ruby using flame fusion method in the late 1800s. These rubies are not considered natural since they are made in laboratory. Nowadays new techniques are used to produce synthetic rubies like Kashan ruby and Chatham ruby which are so close to their natural counterparts in all properties like crystal structure, trace elements, color and hardness that it requires careful observation by a qualified gemologist to distinguish them from natural rubies.
The two most common methods are – Flame fusion and Flux fusion process. The first method is flame-fusion process through which ruby is grown by dropping powder into a flame and freezing it into a synthetic ruby crystal. These stones show curved striae (curved color banding), gas bubbles and flecks of aluminum powder which are not found in the natural rubies. Pulled ruby is technically identical with flame ruby. It is a process in which melted ingredients are dripped into a boule and then allowed to cool at room temperature and pressure to crystallize. By this process rubies are grown very quickly but they do not look glassy therefore easier to separate from the natural stones. They are used extensively in imitation and lower priced jewelry etc.
The second process is the flux growth process which takes longer time, usually months to produce rubies which can pass of as real ones. The crystal structure duplicates flux or the molten chemical. These rubies have inclusions which are found in the natural corundum. These form stress fractures when pressure is released during the manufacturing process. The fractures are then filled with growth solutions healing the fractures but leaving behind a pocket of undigested flux. These fluxes resemble feather or fingerprint inclusions or small specks of platinum which appear to have come from the crucible on which the crystals were grown. The difference in the refractive index of the flux to the corundum makes the flux stand out and help in identifying the ruby as synthetic .The flux inclusions can appear coarse in comparison to the natural inclusions. These stones are cut to near ideal proportion and appear flawless to the naked eye. Unlike flame fusion rubies, these let light bounce around .Flux grown rubies are expensive due to long growth time and low production yield.
Some of the synthetic rubies include Douros from Greece, Chakravorty, Ramaura, Kashm and Chatham which are exceptional in beauty and fineness.
* Kashan Rubies are flame grown showing parallel rod like solid filled, coarse negative crystals which are granular or sugary in nature having high degree of reflectivity. The crystals show wispy pattern resembling rain drops or comets. These contain varying amounts of iron-oxide .Their color is close to many Thai rubies with strong orange dichroism.
* Douros Rubies are produced in Greece and are available since 1995.These are made using flux method in which synthetic magma (flux) is grown under conditions similar to those found in nature. These have attractive visual appearance and reflect high degree of transparency. Their pure red colour surface show hexagonal crystal structure.
* Judith Osmer discovered the process of growing gems after 25 years of sustained research and came up with Ramaura Rubies. These are grown by flux technique in controlled high temperature with molten magma. It is grown spontaneously without a seed with natural inclusions, veils, comet tails, conically shaped feathers, growth lines and color zones. The inclusions consist of various forms of flux particularly coarse orange-yellow flux and white flux fingerprints. These features help in identifying Ramaura Rubies as synthetic. Another distinct feature is presence of fluorescent zoning which occurs in the areas just below the surface. Its intensity varies from high to very high and color ranges from sulphur yellow to yellowish orange to nearly pure orange.
* Ruby doublets are produced by using synthetic or imitation backing with a natural corundum crown. It is often possible to detect them through the glue which joints two pieces together. They show natural inclusions like features and crystals.
* Chatham Rubies came into market as early as 1940s when young Carol Chatham from San Francisco discovered the secret of growing gems in a laboratory. These rubies have features including various form of flux residue. These residues are usually opaque white globules, mesh like patterns and tightly arranged white fingerprints. They reflect hexagonal, triangular, rectangular and spiky platinum platelets which reflect slivery light. The other inclusions are transparent crystals, hammock shaped and net like intertwined feathers.
* Chakravorty Rubies are also made through flux process.
* Knischka synthetic Rubies developed by Prof P.O Knischka can be identified through their spindle shaped multifaceted shape. Other internal features include swirls of colour, irregularly shaped with net like liquid feathers. They show black hexagonal platelets of platinum and silver. The most distinguished feature is two-phase inclusions .The absorption band between 250 and 440 nm indicate that the ruby is synthetic.
Synthetic rubies can be extremely beautiful and affordable. But since they are not natural, they are not considered as gemstones. Besides they can never capture the magic and aura of the real rubies