Longido Ruby

On the Great North Road, between the plains of the Serengeti and the foothills of Mount Kilimanjaro lies the trading town of Arusha, the gateway to the famous gemstones of north-eastern Tanzania. The source of some of the world’s finest gemstones, this area is part of East Africa’s Great Rift Valley, one of the greatest gem deposits on Earth. The ‘classic’ African Ruby source, Longido in Tanzania’s Arusha Region has been yielding beautiful Rubies for close to 100 years. Longido is Tanzania’s first Corundum (Ruby & Sapphire) discovery, and likely the first gemstone deposit discovered in East Africa.

Hardness 9
Refractive Index 1.762 – 1.778
Relative Density 3.97 – 4.05
Enhancement Heat


Named from the Latin ‘ruber’ (red), Ruby’s beautiful hues embody the color of love, passion and romance. Longido Rubies display bright, intense ‘classic’ crimson reds with a medium tone and saturation that are the marketplace ideal. Prized for its color consistency, Longido Ruby looks beautiful when viewed in both natural and incandescent light.

As transparency and inclusions also affect Ruby’s color and subsequent beauty, Ruby is clarity classified by the Gemological Institute of America as a Type II gemstone (some minor inclusions that may be eye-visible). To maintain beauty and quality, our Longido Rubies have been optimally faceted by experienced lapidaries with an eye-clean clarity, the highest quality clarity grade for colored gemstones, a superior polish resulting in a beautiful luster, as well as a good shape and overall appearance (outline, profile and proportions). Optimal lapidary negates color unevenness due to zoning (location of color in the crystal versus how the gem is faceted) and excessive windowing (areas of washed out color in a table-up gem, often due to a shallow pavilion).

Due to the nature of Longido Ruby crystals, most rough is less than 5mm, with faceted gems well under a carat, i.e. 2mm – 6x4mm sizes. Longido Ruby’s small sizes combined with their consistent color makes them perfect for affordable multi-gem designs, when available…

The birthstone for July, Ruby is a truly mesmerizing gemstone with a rich history, potent symbolism, and a popularity spanning over 2,500 years. Ruby and Sapphire are color varieties of the mineral Corundum (crystalline aluminum oxide), which derives its name from the Sanskrit word for Rubies and Sapphires, ‘kuruvinda’. Trace amounts of elements such as chromium, iron and titanium as well as color centers are responsible for producing Corundum’s rainbow of colors.


Far scarcer than Diamonds, Rubies are extremely rare, highly coveted and one of the world’s most expensive gemstones. Ruby sources include Afghanistan, Burma, Cambodia, China, India, Kenya, Madagascar, Mozambique, Pakistan, Sri Lanka, Tanzania, Thailand, and Vietnam. A major international gemstone hub, Thailand is the middle point for approximately 90 percent of the world’s Rubies as they journey around the globe.

Longido Ruby’s discovery occurred during the Battle of Merkerstien (1914 – 1915). Fought under the shadow of Mount Longido, between the British and Germans, a German soldier reportedly, “glimpsed a bright red stone, a Ruby…”. Returning to continue his search at the war’s end, he established a mining company in 1924, which sporadically worked the deposit until its closure in 1971. Reopening in 1988, the mine is operated by the Longido Gemstone Mining Company.

Longido Ruby has uniquely formed as hexagonal red crystals embedded in Anyolite (Green Zoisite and Black Amphibole, whose name is derived for the Maasai word for ‘green’). In fact, Longido is well-known for ‘Ruby Zoisite’, Ruby crystals in bright apple green Zoisite matrix, used as cabochons or carvings. The best Ruby is found in the lighter Anyolite, with the darker rocks yielding darker brownish reds, somewhat similar to Indian Ruby. This combined with the marketplace prevalence of ‘Longido Ruby Zoisite’, leads the uninitiated not to associate this deposit with fine facet grade quality Rubies.

Once Rubies are hammered free of the Anyolite, cobbling is used to remove the heavy inclusions (typical of crystals embedded in their host rock), until they transmit light. Mining is labor intensive, one metric ton of Anyolite only yields 80 carats of useable Ruby rough. Only one percent is cabochon grade, with the amount of facet grade historically too minuscule to record; the rest is only suitable for carving.

A new pocket of high quality, facet-grade Longido Ruby from this famed locale was unearthed in 2017, dramatically increasing the temporary availability of fine Longido Ruby. Interestingly, the discovery went unnoticed by many industry professionals, but for those aware, this is the first time they have seen fine facet grade Longido Ruby in any quantity.

Currently, Longido Ruby is exceptional value for money, especially when compared to comparable gems from better known Ruby deposits. While many gemstone connoisseurs remain unaware of this unique discovery, this is rapidly changing due to its beauty, consistency, clarity, size, versatility and resulting, value for money. With chances of another new pocket similar to 2017 scant, once exhausted, fine Longido Ruby will once again be challenging to source.

Durability & Care

One of the world’s hardest gemstones (Mohs’ Hardness: 9), Longido Ruby is an excellent choice for everyday jewelry. Longido Ruby should always be stored carefully to avoid scuffs and scratches. Clean with gentle soap and lukewarm water, scrubbing behind the gem with a very soft toothbrush as necessary. After cleaning, pat dry with a soft towel or chamois cloth.

Map Location

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