Ruby is a color stone also referred as colored gemstone. It belongs to corundum group of gemstones. Corundum is chemically aluminum oxide. It is found naturally in the nature. Aluminum oxide, when added with coloring agent(s) gets red color and becomes corundum. Coloring agent is also a metallic oxide found and added naturally.
Corundum is the second hardest stone found in the nature. Only diamond is harder than corundum.
Ruby originating countries: Burma (Myanmar), Ceylon, Thailand (Siam), Cambodia, Vietnam, Tanzania, Madagascar, Kenya and India are major sources of ruby. However, Burmese rubies are considered as the best. Origin or mine of ruby plays a major role in determining its valuation. It is therefore, advised to know about origin before buying a ruby.
Four “C”s of ruby gemstone
Like any other gemstone four “C”s play major role in determining value of ruby. These four “C”s are Cut, Clarity, Color and Carat weight. It is better to know about four “C”s before buying a ruby.
Cut:There are various types of cuts in ruby gemstone. These are cut, cabochons, beads, drops etc. Cut stones are the costliest followed by cabochons and beads. Cut stones are faceted but cabochons are plain. Beads and drops are manufactured both in faceted and plain quality.
There are various shapes in both cut and cabochons such as Oval, Octagon, Pear, Heart, Marquise, Square and Round.
More inclusions means lesser clarity (purity). Clean is rare and fetches highest price. Ruby with better purity has more price and with lesser purity has lower price.
Color shades:Color of ruby varies between light pink to deep pigeon blood red. Sometimes it has blue, yellow or black tints. A ruby is generally referred as Pink sapphire if the color is pink. Light color fetches lesser price than deeper color. However, over color rubies fetch lower price. Generally bright red is the costliest. Blue, yellow and black tints present in ruby lower the price of a ruby gemstone.
Burmese ruby has the most pleasant bright pink to red color. Ceylon ruby is normally of pink color and Thai ruby has black tints. Bright color and transparency of Burmese ruby fetches maximum price. Hence, you can stress on Burmese origin while buying a ruby.
Carat weight: Bigger the size more the price. It is true for good quality rubies. Fine quality rubies of bigger sizes are rare. Generally fine quality Burmese rubies above 3- 4 carats are rare. Sizes between two to four carats for a fine quality Burmese ruby is considered as very good.
Treatments And Synthetics:Natural rubies are also treated to enhance its color, clarity and transparency. Most popular treatment is heat treatment. Natural rubies are costlier than treated rubies. There are some other treatments such as glass filling and led filling. Glass filling enhances clarity of rubies and led filling enhances both clarity and color. However, led filling is injurious to health.