Are rubies in Retro jewelry usually synthetic?

Often, yes. Synthetic corundum was inexpensive and used openly from the early twentieth century, particularly in 1940s gold. It is period correct, and we say so plainly when a stone is synthetic.

What is glass filled ruby?

Low quality ruby whose fractures are filled with lead glass to improve appearance. It is fragile, worth a fraction of untreated ruby, and must always be disclosed.

Is heat treatment acceptable in ruby?

Yes. Heating is stable, permanent and standard for corundum. An untreated stone of fine color commands a substantial premium and should be certified.

Gemstone encyclopedia

Ruby — meaning, history and vintage jewelry

Ruby is the red variety of corundum, the same species as sapphire, colored by chromium. At 9 on the Mohs scale it is one of the most durable gems there is. Fine untreated Burmese ruby is one of the rarest materials in the gem world, and it is worth more per carat than diamond at the top of the market. Heat treatment is common and accepted; glass filled ruby is a different, much lower value product and must be disclosed.

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What ruby is

Color drives everything. The trade term pigeon's blood describes a pure, slightly fluorescent red, historically associated with Burmese material. Thai and later Mozambican rubies tend darker or more garnet toned.

Rubies of any size are genuinely rare, which is why antique pieces so often use small calibre cut rubies as accents rather than as a center stone. Any large ruby presented as untreated should be supported by an independent report.

Color and hardness

Species: Corundum
Color: Red, from purplish through to a slightly orange pigeon's blood
Mohs hardness: 9
What that means in wear: Second only to diamond in hardness, with no cleavage. Excellent for daily wear.

How to care for ruby

Warm soapy water and a soft brush. Ruby tolerates cleaning well.
Avoid ultrasonic cleaning on glass filled or heavily fractured stones, and on any antique closed back setting.
Have claws checked; the stone will outlast the mount.

Our full house rules, including what the one year warranty does and does not cover, are in the care & warranty guide.

History and symbolism

Burmese mines at Mogok supplied Europe for centuries. In the nineteenth century, before synthetic corundum was understood, red spinel was frequently sold as ruby, which is why several famous historic rubies are now known to be spinels.

Passion, courage and vitality. Ruby was traditionally the stone of protection worn by soldiers and kings.

Ruby in vintage and antique jewelry

Victorian ruby and diamond clusters; Edwardian platinum work with calibre cut ruby borders; Art Deco geometry using ruby as a graphic red; Retro gold rings with cabochon or synthetic ruby, which was widely and openly used in the 1940s.

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Ruby pieces in our collection

Every curated vintage, antique and estate piece is one of a kind and checked by our jewelry specialists in the Netherlands. If nothing is right today, we will look for it.

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Frequently asked questions

Are rubies in Retro jewelry usually synthetic?: Often, yes. Synthetic corundum was inexpensive and used openly from the early twentieth century, particularly in 1940s gold. It is period correct, and we say so plainly when a stone is synthetic.
What is glass filled ruby?: Low quality ruby whose fractures are filled with lead glass to improve appearance. It is fragile, worth a fraction of untreated ruby, and must always be disclosed.
Is heat treatment acceptable in ruby?: Yes. Heating is stable, permanent and standard for corundum. An untreated stone of fine color commands a substantial premium and should be certified.

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