Summary
Although non-gem corundum occurs abundantly all over the world, gem-quality ruby and sapphire are significantly rarer. Their sources are also more restricted. Since ruby and sapphire origins play a major role in determining the value of these gems, gemologists, jewelers, and consumers alike should learn where these prized stones come from.

Determining ruby and sapphire origins can be difficult, but the inclusions in these gems can help identify where they were mined.

Reading time: 9 min
Rock Creek sapphires - matched pair

Matched pair of blue sapphires, 1.23 ctw, from Rock Creek, Montana. Photo © Joel E. Arem, PhD, FGA. Used with permission.

Ruby and Sapphire Origins and Geology

Both ruby and sapphire are corundum, just with different colors. Gem-quality red corundum is considered ruby, while all other colors of gem-quality corundum, including colorless, are sapphire.

The mineral corundum forms in metamorphosed crystalline limestones and dolomites, as well as other metamorphic rock types such as gneiss and schist. It also occurs in igneous rocks, such as granite and nepheline syenite. Miners often find gem corundums in placer deposits.

You can learn more about the formation and chemistry of rubies and sapphires here.

pastel yellow sapphire - Sri Lanka

Pastel yellow sapphire, round brilliant cut, 1.90 cts, 7.2 mm, Sri Lanka. © The Gem Trader. Used with permission.

Asia

Myanmar (Burma)

Ruby historically comes from the Mogok stone tract. The history of the mines here is long, complex, and turbulent. Gems occur in a gravel layer called byon at a depth of 20 to 100 feet. Miners recover them by washing and screening with broad screens, then handpicking promising pebbles. Corundum originates in metamorphic marbles that have largely weathered away. This is the source of the world’s finest rubies.

Burmese ruby

“Pigeon’s blood red” ruby crystal from the “Valley of Rubies” in Mogok, Myanmar, 3.9 x 2.7 x 2.5 cm, 23 g. © Rob Lavinsky, www.iRocks.com. Used with permission.

Kashmir

Fine sapphires occur in northern India in the NW Himalayas at an elevation of nearly 15,000 feet, in a deposit snowed under most of the year. Gems occur in a pegmatite and in the valley below, in surface debris. These sources are now exhausted.

Extremely scarce, Kashmir sapphires have a cloudiness due to inclusions and an extremely good blue color, making them greatly desired.

Kashmir sapphire

Kashmir sapphire, untreated, 5.13 cts. Photo courtesy of liveauctioneers.com and Simrit Collections.

Pakistan

Ruby and spinel of fine quality occur in the Hunza Valley on the Pakistan Side of the Kashmir Valley. The color is comparable to Burma ruby but the material is heavily flawed.

Thailand

The areas of major importance here are Chantabun and Battambang. The corundum deposits have only been worked in a major way in modern times. Miners find gems in a sandy layer within 6 to 20 feet of the surface and recover them by washing.

Thai rubies rose to importance on the market because of the scarcity of Burmese gems.

yellow sapphire - Thailand

Radiant-cut yellow sapphire, heated, 1.39 cts, 7.5 x 5.5 mm, Thailand. © The Gem Trader. Used with permission.

Cambodia

Pailin produces some of the world’s finest sapphires, but the country isn’t a significant ruby source.

Sri Lanka

Sri Lanka is a source of many colors of sapphire, as well as ruby and star gems. Gems occur here in a gravel layer known as illam at a depth of up to 50 feet. Miners wash and screen the material and recover gems by hand.

Sri Lankan ruby isn’t as good as Burmese material, and the sapphires are often pale in color but can be very large.

Geuda sapphires - Sri Lanka - ruby and sapphire origins

Geudas are whitish, milky sapphires frequently found in Sri Lanka. With heat treatments, they can show fine blue as well as yellow and orange colors. Photo © Joel E. Arem, PhD, FGA. Used with permission.

Afghanistan

Ruby of fine color has come from Jegdalek, near Kabul. This is an ancient source of many of the fine stones of ancient times.

ruby crystal - Afghanistan

“Ruby Heart” on white marble matrix, 1.5 cm across, Jegdalek, Sorobi District, Afghanistan. © Rob Lavinsky, www.iRocks.com. Used with permission.

India

Mysore usually produces poor-quality rubies but a significant amount of star ruby. However, occasionally, this area produces stones of excellent quality.

ruby crystal - India

Ruby crystal, 4.3 x 3.5 x 2.6 cm, Mysore, Karnataka, India. © Rob Lavinsky, www.iRocks.com. Used with permission.

Japan

Amphibole-zoisite rock on Mt. Gongen, Hodono Valley, Ehime Prefecture has yielded transparent crystals to 5 cm.

Vietnam

Vietnam produces rubies as well as sapphires in a variety of colors.

star ruby - Vietnam

Pinkish red star ruby, 3.45 cts, Vietnam. Photo courtesy of liveauctioneers.com and Jasper52.

Nepal

Nepal produces some gemmy ruby crystals, typically with heavy color zoning.

ruby - Nepal

Ruby crystals, 4.1 x 3.2 x 2.1 cm, Chumar Mines, Dhading District, Bagmati Zone, Nepal. © Rob Lavinsky, www.iRocks.com. Used with permission.

Australia

Anakie, Queensland produces some ruby as well as sapphire in blue, green, and yellow shades, all in alluvial deposits. Some fine green gems are known, as well as an occasional excellent blue gem.

Other occurrences include New South Wales, especially the Inverell district (often referred to as the New English fields). Victoria also produces green sapphire.

Ruby has been found in the Harts Range, Northern Territory.

black sapphire - Australia

Oval-cut black sapphire, 0.91 cts, 7.1 x 5.2 x 2.7 mm, heated, Australia. Photo courtesy of liveauctioneers.com and Treasure of Gems and Jewelry.

United States

Montana

Yogo Gulch is a well-known locality for fine blue sapphire of very good color that occurs in igneous dikes. The crystals are very flattened and waterfall-like, so it’s difficult to cut large, full-cut gems from them. Crystals occur in many different colors and are usually quite small, but the blue stones are extremely fine. Often zoned, this material may have a curious metallic-like luster.

The gravels of the Missouri River, Rock Creek, Dry Cottonwood Creek, and the Gem Mountain Sapphire Mine in Philipsburg also produce sapphires.

Ruby is uncommon here.

fancy sapphires - Rock Creek, Montana

“Fancy sapphires” are those with colors other than classic, well-known blues. These fancy sapphires hail from Rock Creek, Montana. Photo © Joel E. Arem, PhD, FGA. Used with permission.

North Carolina

At Cowee Creek, in Macon County, small rubies and sapphires are found in stream gravels and soil. The quality is usually poor, but an occasional fine, small ruby is found.

The Cherokee Mine at Franklin yields rubies and sapphires.

South America

Brazil

The Matto Grosso area has produced sapphires.

blue sapphires - Brazil

Parcel of oval-cut blue sapphires, Brazil. Photo courtesy of liveauctioneers.com and Collector’s Liquidation.

Colombia

Miners have found blue and violet sapphires, many showing a distinct color change, near Mercaderes, Cauca, Colombia, probably originating in alkalic basalts. Crystals are prismatic and rounded, up to 3 cm in size. Typical colors include blue (somewhat pale), green-brown, and violetish, but some yellow, pink, and red crystals also occur. Some star material also exists. The stones are rich in iron and poor in titanium. Metallic rutile crystal inclusions are typical.

Europe

Gem-quality corundum is occasionally found in the Czech Republic, Finland, Greenland, Norway, and Russia.

opaque ruby crystals - Norway

Opaque ruby crystals on granitic matrix, largest 1.5 cm across, Froland, Aust-Agder, Norway. © Rob Lavinsky, www.iRocks.com. Used with permission.

In Scotland, facetable blue sapphire crystals, up to about 45 mm in diameter, occur at Loch Roag, Isle of Lewis, in the Outer Hebrides. Their colors are variable and sector zoning has been observed, with a paragenesis similar to that of Pailin, Cambodia. Cut stones usually weigh a maximum of 2-3 carats.

Africa

Tanzania

Large ruby of fine color and quality is found in green, massive chromiferous zoisite (“ruby-in-zoisite”). The crystals are usually opaque, and the rock as a whole is cut as a decorative material, but occasionally some small areas of this ruby are transparent enough to facet.

Many colors of sapphire are found in the vicinity of Morogoro, Tanga Province, along with some ruby. The Umba River Valley is also a source of fine sapphires in a wide range of colors.

orange sapphires - Songea, Tanzania

Orange sapphires, Songea, Tanzania. Photo courtesy of liveauctioneers.com and Pristine Gems.

Zimbabwe

Sapphires of various colors are found here, often zoned with a creamy-white core and blue outer zone, or vice versa. The well-formed crystals usually measure up to 3 inches in diameter. At the Baruta Mine in Northeast Zimbabwe, a deep blue crystal of 3,100 carats was found.

Zimbabwe is also a source of black star sapphire. However, sapphires from here remain relatively unknown on the market.

Kenya

Excellent ruby is known from a small ruby mine. The ruby has a pinkish but fine color and usually occurs in small sizes. Sapphires have also been found.

multi-colored sapphire - Kenya

This 2.40-ct, rectangular step-cut sapphire from Kenya shows dark blueish-green, green-yellow, and brown colors. © The Gem Trader. Used with permission.

Mozambique

Montepuez produces rubies and sapphires.

ruby - Montepuez, Mozambique

2.52-ct ruby, heated, Montepuez, Mozambique. Photo © David and Melanie Fortier of Paragon Universal Trade in Bangkok. Used with permission.

Madagascar

Madagascar produces rubies as well as blue and pink sapphires.

blueish purple sapphire crystal - Madagascar

Blueish purple sapphire crystal on schist matrix, 9.1 x 5.3 x 4.0 cm, Zazafotsy Quarry (Amboarohy), Zazafotsy Commune, Ihosy District, Horombe Region, Fianarantsoa Province, Madagascar. © Rob Lavinsky, www.iRocks.com. Used with permission.

Malawi

Sapphires were found at Chimwadzulu Hill around 1958.

Namibia

Opaque ruby suitable for cabochons occurs at Namaqualand.

What Can Inclusions Reveal About Ruby and Sapphire Origins?

In general, Burmese, Thai, and Australian blue sapphires contain crystals of plagioclase feldspars, orthoclase, niobite, columbite, calcite, monazite, zircon, apatite, fergusonite, and thorite.

  • Tanzania: sapphires may contain crystals of chlorapatite, pyrite, magnetite, biotite, graphite, phlogopite, zircon, and spinel. Umba River Valley sapphires may contain apatite, graphite, and pyrrhotite. Longido sapphires may contain pargasite, spinel, zoisite.
  • Brazil (Jauru, Matto Grosso): rounded gas-filled discs that resemble bubbles.
  • Burma (Mogok): short rutile needles at 60⁰ angles; silk consisting of hollow tubes plus crystals of rutile, spinel, calcite, mica, garnet, zircon crystals with haloes; color swirls known as treacle.
  • Thailand: feathers, canals and tube-like liquid inclusions; flat, brownish cavities; twin planes; crystals of niobite, almandine, apatite, pyrrhotite, plagioclase crystals in sapphires. Rutile is absent.
  • Sri Lanka: long rutile needles; healing cracks; zircon crystals with haloes; flakes of biotite and phlogopite mica; feathers with irregular liquid hoses inside; color zoning is frequent; crystals of spinel, graphite, ilmenite, apatite.
  • Pakistan (Hunza Valley): inclusions of phlogopite, chlorite, monazite, spinel, rutile, magnetite, pyrite, calcite.
  • Cambodia (Pailin): specks of uranian pyrochlore (ruby red color, very small).
  • Kashmir: yellow and brown feathers and thin films; liquid-filled canals; veil-like lines at 60⁰ and 120⁰; cloudy haziness; negative crystals (cavities); flat films; rods and tubes.
  • Australia: discoloration and twin lamellae (plates); rutile crystals; liquid-filled feathers, flat cavities; color zoning is frequent.
  • Nepal: undulating veils, strong color zoning, prismatic crystals, margarite.
  • Malawi (Chimwadzulu Hill): fine tubes; small black crystals and short rods; healed fissures; color zoning.

For information on inclusions typically found in corundum, consult our article on identifying inclusions found in specific gems.