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Star Rubies

A star ruby is a ruby cut as a cabochon that shows a six-rayed star, an effect called asterism produced by light reflecting from fine needles of rutile aligned in three directions inside the crystal. Fine star rubies, with a sharp, centred star over a true red body, are rare; most are greyish, purplish or opaque. Byrex Gems offers star rubies to the trade from Toronto, filmed unedited in our office, with prices for approved buyers and viewings by appointment.

Where to buy star rubies in Toronto

Byrex Gems lists 2 star rubies online today. 2 of them come with a report from laboratories including GRS and Gübelin. Viewings are at our Toronto office, 27 Queen Street East, Suite 407, steps from Queen subway station, by appointment. We have supplied coloured gemstones and natural fancy colour diamonds to jewellers and designers since 1988, and welcome private clients by appointment. Prices are shown to approved trade accounts; private clients can ask us on WhatsApp, where we reply within 12 hours, or by email within 24 hours. Every stone ships insured, worldwide.

Among the star rubies listed today: 12.43 ct Star Oval Ruby, Gübelin + IGI, Burma Unheated, 15.09 ct Oval Cabochon Star Ruby, GRS, Burma Unheated.

What makes the star in a star ruby

The star is made of silk. Needles of rutile, titanium oxide, grow inside corundum along three directions of the crystal's hexagonal structure, crossing at sixty degrees. When the stone is cut as a cabochon with its base parallel to the crystal's basal plane, each set of needles reflects a band of light across the dome, and the three bands meet in a six-rayed star that moves as the stone or the light moves.

The same rutile that makes the star takes transparency away, so a star ruby is a compromise between enough silk for a sharp star and little enough for a saturated, translucent body. Twelve-rayed stars occur rarely when a second set of needles is present.

Burma, and Mogok in particular, has produced the finest star rubies, with strong red bodies and crisp stars. Sri Lanka produces many, often lighter or pinkish; Vietnam, Mozambique, Madagascar and Tanzania contribute, and India's Mysore district supplies large opaque material. Chromium gives the red, and the same iron rule applies as in faceted ruby: low-iron stones glow, iron-rich stones go dull.

How laboratories describe star rubies

A report identifies the stone as natural corundum, variety ruby, and notes asterism as a phenomenon; GIA, GRS, SSEF, Gübelin, Lotus and AGL all report on cabochons. Origin opinions follow the same method as for faceted stones, from inclusions and chemistry, and can be stated as inconclusive.

Treatment is where star rubies differ. High-temperature heating dissolves rutile, so a stone with a sharp star has not been heated hard enough to destroy its silk, and most star rubies read "no indications of heating". The common treatment at the low end is lead-glass filling of fractures, which laboratories disclose and GRS codes H(d); it leaves the star intact and the stone fragile.

Synthetic star corundum has existed since the late 1940s and shows a star that is too perfect, floating on the surface of a body with no natural inclusions; diffusion can also induce a star on treated material. A laboratory separates all of these by inclusions, spectra and chemistry, which is why a report matters as much for a cabochon as for a faceted stone.

How to judge a star ruby before buying

Judge the star under a single point of light, a penlight or the sun, not under diffuse showroom lighting that flatters every stone. The six rays should be complete, straight, equal in length and sharp to their tips, and the star should sit in the centre of the dome when the stone is viewed from the top. A star that drifts to one side was cut off-axis to save weight.

Then judge the body. The colour should read red, not purplish grey or pink, and the stone should be translucent enough to show depth rather than opaque. Move the stone and watch the star glide smoothly; a star that jumps or breaks indicates uneven silk.

Look at the proportions. A good cabochon has a moderate dome, a flat or slightly convex base and little excess weight beneath the girdle, because the base is paid for by the carat and contributes nothing. Check the polish and, with the report in hand, any note of filling. Pairs for earrings need matching star sharpness as well as colour, and are rare. For setting, a bezel or four strong prongs suits a cabochon, and an unfilled star ruby takes normal bench handling.

What drives the value of a star ruby

Body colour leads, as it does in every ruby. A saturated red body with a translucent depth is worth more than a sharper star over a grey or pink body, because the star can be admired on any stone but the colour cannot be added. Star quality comes next: sharpness, centring and completeness.

Transparency follows, then size, then origin, with Burma at the top and Sri Lanka's lighter stones below, and treatment runs through all of it; an unfilled, unheated star ruby is the standard and a glass-filled star is a different product. Large sizes exist because silky rough is more plentiful than clean rough, so weight alone impresses less in star rubies than in faceted ones.

Fine star rubies in the sizes most jewellery uses are scarce, and the market for them is driven by collectors and by jewellers who want a cabochon with a report rather than a curiosity.

Famous star rubies and their look-alikes

The two most famous star rubies are in American museums. The Rosser Reeves Star Ruby, a 138.7 carat Sri Lankan stone, is at the Smithsonian in Washington. The DeLong Star Ruby, a 100.32 carat Burmese stone, is at the American Museum of Natural History in New York and was among the gems stolen from the museum in 1964 and later recovered.

Star sapphires are the nearest relatives, and the line between a star ruby and a purplish-red star sapphire is drawn by the laboratory. Star garnet from India and Idaho shows four or six rays over a dark red-brown body and is easily told apart with a loupe. Synthetic star corundum and glass with painted or engraved stars are the imitations to know.

Byrex keeps star rubies for the trade because a fine one, with a report, is a stone a designer can build a piece around, and because the demand for honest cabochons outstrips the supply.

Buying star rubies from Byrex Gems

A star has to be seen moving, so every star ruby we list is filmed in our office, and further video is a message away. Byrex Gems has been in Toronto since 1988, and more than seven thousand trade customers in Canada and abroad have bought from us. Many of our star rubies come with reports from GRS, SSEF, Gübelin, GIA and other leading laboratories.

Approved trade buyers see prices online. Others may write at any hour: WhatsApp +1 (437) 450-3786 is answered within hours and email to info@byrex.com the same day, seven days a week. What is listed is a part of what we hold: more star rubies are kept in the vault, and what we do not hold ourselves we can source through our offices worldwide. Private viewings are arranged by appointment in Toronto, Hong Kong, Bangkok and Dubai.

Star Rubies: questions buyers ask

Where can I buy star rubies in Toronto?

Byrex Gems lists 2 star rubies online today. 2 of them come with a report from laboratories including GRS and Gübelin. Viewings are at our Toronto office, 27 Queen Street East, Suite 407, steps from Queen subway station, by appointment. We have supplied coloured gemstones and natural fancy colour diamonds to jewellers and designers since 1988, and welcome private clients by appointment. Prices are shown to approved trade accounts; private clients can ask us on WhatsApp, where we reply within 12 hours, or by email within 24 hours. Every stone ships insured, worldwide.

What causes the star in a star ruby?

Fine needles of rutile growing in three directions inside the corundum crystal. Cut as a cabochon aligned with the crystal, each set of needles reflects a band of light and the three bands cross to form a six-rayed star that moves with the stone.

Are star rubies usually heated or treated?

Rarely with high heat, because heating hot enough to improve colour dissolves the silk that makes the star. Most star rubies carry reports reading no indications of heating. The treatment to watch for is lead-glass filling of fractures in lower grades, which laboratories disclose.

How do I tell a good star from a poor one?

Use a single light source. The six rays should be straight, complete, equal and sharp, and the star should sit in the centre of the dome when the stone is viewed from the top. A star that drifts, breaks or only appears under diffuse light is a lesser star.

Which reports does Byrex supply with star rubies?

Star rubies at Byrex carry reports from GRS, SSEF, Gübelin, Lotus, GIA or AGL that identify the stone, note asterism, state treatment and give an origin opinion. GRS reports are shown on the stone page, and a further report can be arranged on request.

Is a star ruby worth less than a faceted ruby?

Usually, carat for carat, because the silk that makes the star reduces transparency and most star material is lower in colour. A fine star ruby with a saturated red body and a sharp star is a rarity in its own right and is priced as one.

Does Byrex sell star rubies to private clients?

Yes, by appointment at 27 Queen Street East, Suite 407, Toronto. Private clients see the same stones and reports as the trade, with prices released to approved trade buyers who sign in. Byrex can also source a star ruby or a matched pair to a brief.

Can I see star rubies in Toronto?

Yes. Book an appointment and the stones are shown under a single light source, which is the only honest way to judge a star, with their reports beside them. Each stone is also filmed unedited in our office so you can watch the star move beforehand.

How should a star ruby be set?

A bezel or four substantial prongs suits a cabochon, with the dome exposed to light from above so the star shows. Keep the base supported. An unfilled star ruby takes normal bench handling; a glass-filled one must be kept away from the torch and acids.

Byrex Gems, 27 Queen Street East, Suite 407, Toronto. Coloured gemstones and natural fancy colour diamonds for the trade since 1988, and for private clients by appointment.

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