Star Ruby Gemstone Information

Star ruby is a rare variety of ruby that exhibits asterism; a six-rayed star that shimmers over the surface of the stone when it is moved. The star effect is owed to aligned needle-like rutile inclusions. It is the rutile which is responsible for its silky shine. In rough form, ruby is dull and greasy, but when cut and polished its luster is comparable to fine diamond. Ruby is classified as the red form of gem-quality corundum; all other color varieties of corundum are referred to as sapphire. Corundum is the second hardest mineral on the Mohs scale, with a hardness rating of nine. Owing to its superior hardness combined with its rich color and silky shine, fine quality ruby is classed as one of the group of four so-called "precious" stones, along with diamond, emerald and sapphire. Ruby gets its name from the Latin word 'ruber', which means red.

Rubies can range in color from pinkish red to orangey, purplish and brownish-red, depending on their chromium and iron content. The most desirable color is 'pigeon's blood red' - a pure red with a hint of violet or blue, only found in the mines of Myanmar (Burma). Star ruby, along with all other forms of ruby, is one of the most valuable types of colored gemstones available today. In fact, large rubies are actually rarer and more valuable than diamonds of comparable size. Ruby is the official birthstone for those who are born in July. Ruby may be also used to celebrate 15th and 40th wedding anniversaries.

Identifying Star Ruby Star Ruby Origin Buying Star Ruby Star Ruby Gemological Properties Star Ruby; Related Gems Star Ruby Mythology Star Ruby Jewelry Famous Star Ruby Gemstones Star Ruby Gemstone Care

Shop Star Ruby Cabochons Click to enlarge image

For centuries, the most important deposits have been in Upper Myanmar (Burma) near Mogok. Only one percent of the production is of gem quality. Some of the rubies are of pigeon's blood color and considered to be the most valuable rubies of all. In the early 1990s, large new deposits were discovered at Mong Hsu.

Thailand: Rubies found in Thailand (Chanthaburi Province) often have a brown or violet tint. Unfortunately, Thai ruby production is in decline.

Sri Lanka: The deposits are located in the southwest of the island in Ratnapura District. Rubies from these deposits are usually light-red to raspberry red.

Tanzania: On the upper Umba River in Northwest Tanzania there are gemstone quality ruby deposits that are violet to brown-red. A few opaque rubies are mined there as well.

Other deposits of importance are found in Afghanistan, Cambodia, Kenya, Madagascar and Vietnam.

Less important deposits are found in Australia, Brazil, India, Malawi, Nepal, Pakistan, the United States and Zimbabwe.

Star Ruby Color

Star rubies range in color from pinkish to orangey or purplish and brownish-red, depending on their chromium and iron content. The most desirable color is the so-called "pigeon's blood," a pure red with a hint of violet or blue. The distribution of color is often uneven in strips or spots. Color saturation is extremely important.

Star Ruby Clarity and Luster

Transparent ruby is favored, but star ruby actually requires welcomed inclusions. Most star ruby is opaque with some finer materials exhibiting slight translucency. Rutile inclusions cause the six-rayed asterism that converts a ruby into the desired star ruby. The rutile lends ruby a silky luster. Inclusions are common for star ruby and are not always indicative of poor quality. Inclusions commonly found in ruby are used to help distinguish between natural and synthetic ruby. Inclusions may also be used to help distinguish origin.

Star Ruby Cut and Shape

Star rubies are typically cut en cabochon with very high domes to maximize asterism. Large star rubies are considered very rare. Pear shapes and ovals are most common. Most star ruby gemstones are native cut; this is common for most types of cat's eye and star gemstones. Cutting of star ruby often necessitates uneven bottoms in order to properly orient and best display asterism (star effect).

Star Ruby Treatment

The most common treatment for star ruby is heat treatment. Generally before stones are cut, they are heated to between 1700 to 1800 degrees Celsius (3100-3300 degrees F) for several hours. Heating often improves color and clarity. Fracture-filling treatments for star ruby are now becoming more and more common in the gem markets.

Please refer to our Gemstone Glossary for details of gemology-related terms.

Star Sapphire

Star ruby is a sub-variety of traditional ruby which is the red colored member of the corundum group. Ruby is closely related to sapphire and thus shares many gemological properties such as hardness, composition and double refraction. Varieties of corundum gemstones include sapphire, star sapphire and color change sapphire. Cat's eye ruby and trapiche rubies are available but also quite rare. Trapiche rubies consist of a fixed star and are often cut and traded in slices. Some trapiche rubies may also display asterism, but such stones are incredibly rare. Star ruby may be easily confused with red garnet or spinel. Some reddish topaz, tourmaline and zircon may also cause confusion.

For a long time India was considered the classical source for rubies. In the Sanskrit language ruby is called "ratnaraj," which translates as "king of gemstones." In ancient times one of the chief attractions of ruby has been a belief in its protection from misfortune and bad health. Ruby is the birthstone for those who born in July. In the zodiac scheme, ruby is sometimes associated with Capricorn. Ruby is also used to celebrate a couple's 15th and 40th anniversaries. In Antiquity, as well as in the Middle Ages, people believed that the cosmos was reflected in gemstones. Ruby is assigned to the planets Mars and Pluto. The esoteric movement revived this ancient belief and the gem industry made it another marketing tool to promote certain gems. The healing powers of gems remain a controversial issue, but have been mentioned for centuries by healers, shamans and medicine men. Whether it's based on fact or a placebo effect is unimportant, if it helps. The safest approach is to wear the gemstone in direct contact with the troubled part of the body. Ruby is said to be a general health protector and, in particular, to be good for backache and toenail problems.

Rubies have been used as gemstones for centuries. Ruby is one of the most durable materials and can be worn daily in gemstone rings, earrings, necklaces, bracelets, pendants, pins and brooches. Opaque ruby is often used for carvings. Gold settings provide a striking contrast to the color of red ruby. Star ruby is ideal for jewelry which is most exposed to direct light, such as a cabochon ring. Star ruby is rarely available in large sizes, so most jewelry will feature small stones. Star gemstones are very popular for men's jewelry.

Note: Buy colored gemstones by size and not by carat weight. Colored stones vary in size-to-weight ratio. Some stones are larger and others are smaller than diamonds by weight in comparison.

Famous star ruby stones of outstanding beauty and color are the "Rosser Reeves Star Ruby," of 138.7 ct, which can be seen at the Smithsonian Institution in Washington, and the "De Long Star Ruby," weighing 100 ct, at the American Museum of Natural History in New York.

Star ruby is typically very durable and considered to be one of the hardest materials. It is slightly softer than diamond, but it lacks cleavage which makes it resistant to fracturing. Fracture-filled ruby is not as durable as untreated star ruby. It is not advisable to recut or repolish star rubies that have been fracture-filled. Star ruby can be brittle, so care should be taken when cutting and setting. For cleaning, it is best to use only warm soapy water and a soft cloth. As with most gemstones, avoid the use of ultrasonic cleaners and heat steamers, especially with fracture-filled star ruby. The vibrations and heat can permanently damage your stones.

Always remove any jewellery or gemstones before exercising, cleaning or engaging in harsh physical activities such as sport. Do not expose rubies to acid and store rubies away from other gemstones to avoid scratches. It is best to wrap gemstones in soft cloth or place them inside a fabric-lined jewelry box.