Labradorite: meaning, properties and lore

The mineral

Labradorite is a plagioclase feldspar and a lime-soda feldspar, belonging to the feldspar group of minerals. The plagioclase series forms a solid solution between anorthite and albite, and feldspar has orthoclase, albite and anorthite as end members. Its composition is written as a mix of albite and anorthite, with labradorite sitting in the calcic part of that series.¹²³⁷

Labradorite sunstone has a composition of Ab50–30An50–70, and Oregon sunstone is about 70% anorthite and 30% albite, written An70/Ab30. Material from the Minnesota gabbro varies between Ab50An50 and Ab70An30, and the composition of labradorite in general varies from andesine to near anorthite in different examples.⁸¹²⁹⁴

Labradorite has a hardness of 6 on the Mohs scale and a specific gravity of about 2.72. It takes a high polish. Its body colour is usually gray, brown or greenish, and the colour flashes stand out against a dark gray or black background.³

The iridescent effect, known as labradorescence, comes from light interfering with thin, internal lamellar layers within the crystal. Those layers form during the cooling of the mineral. Labradorescence is most commonly blue but can also be green, gold, orange and even violet, and the iridescence relates to light interacting with thin film structures or platy particulate inclusions.⁵⁶

The golden and red metallic lustre of sunstone comes from microscopic metallic inclusions, which are tiny reflective platelets of native copper called schiller. Red colour in Oregon labradorite sunstone is attributed to copper, present as native copper and cuprite in thin films, with green from similar mixtures in short microcolumns. Sunstone ranges from near-colourless to pale yellow to red and green, and some examples show red to green dichroism.¹²⁸

Microprobe analyses of colourless, red and green samples did not reveal an obvious cause for the colours. Ongoing research is investigating intervalence charge transfer, possibly involving colloidal copper, as a cause of the colours. The material shows a wide range of saturated body colours, aventurescence and strong pleochroism.⁸

Cat's-eye labradorite is cut from stones containing parallel needle inclusions aligned with crystallographic directions. Spectrolite is a rare variety from Finland that displays a range of hues and stronger labradorescence, often showing several colours at once. A transparent variety is sometimes called rainbow moonstone, though it is not strictly considered a moonstone species.⁵⁶

Labradorite sunstone is reported from Oregon, United States, and the Afar region of Ethiopia. In eastern Oregon it occurs at the Ponderosa mine near Burns, the Dust Devil mine and the Sunstone Butte mine, where it forms phenocrysts in highly porphyritic basalt flows. Those crystals formed in basaltic lavas about 15–17 million years ago during the Miocene epoch. Labradorite is also found in the Labrador series across Canada, in Essex county, New York, the Isle of Skye, Norway and southwestern Russia.¹²³⁴

Gemological identification of this material uses refractive index, specific gravity and microscopy. Determining the Oregon locality is based on the copper inclusions and a distinct pleochroism. Labradorite is a relatively inexpensive plagioclase feldspar and has since been identified in locations all over the world.⁸⁷⁵

History and lore

A later account says the stone of Labrador was unknown until about a hundred years before that account, when it was discovered on the Island of St. Paul near the coast of Labrador.⁵⁷

Hunt wrote that the name norite, alluding to Norway, was given by Esmark to a rock composed chiefly of labradorite found in Norway. An ornamental vase of labradorite rock, turned in a lathe with a black diamond, has been in the Museum of the Geological Survey of Canada since 1856.⁴

Hunt described labradorite as the characteristic mineral of the rocks he called labradorite rock, which he said make up most of the Labrador series. In those rocks the labradorite is generally smoky gray, translucent and opalescent with greenish reflections, and its colours run from bluish-black or violet to bluish-gray, smoky gray or lavender. Labradorite feldspar often shows cleavage planes two inches broad at Square Island on the Labrador coast, and labradorite rock occurs as large blue masses on Marblehead Neck on the coast of Massachusetts.⁴

Rose formed labradorite as one of the four great species from the ancient felspar group, and labradorite has been found in its crystallized state scattered through volcanic productions, notably in the lavas of Etna. The finest labradorite colours are a play of blue and green upon grey, with yellow and bronze-red less common and pearly-grey and purple-red rarer still.⁷

Schrauf named the colored squares and plates microplakites and microphyllites, which he thought were probably the efficient cause of the iridescence for which certain labradorites are famous. Von Kobell first correctly determined pectolite in 1828 on material from the Tyrol, a mineral found in the discussion of secondary minerals formed from labradorite.⁹

Stewart (1966) gave a composition of An67.2/Ab31.5/Or1.3 for the larger feldspar phenocrysts and proposed primary crystallization at about 1100°C. Johnston (1991) characterized Ponderosa labradorite as 70% anorthite and 30% albite, placing it at the labradorite/bytownite boundary. Oregon sunstone became the official state gemstone of Oregon in 1987.²

Birthstone, zodiac and chakra links

Crystal practitioners link labradorite with the zodiac sign of Aquarius, an association that is modern rather than ancient.¹⁰¹¹

Crystal practitioners primarily associate labradorite with the Third Eye chakra, also called the Ajna chakra, and this is a modern link. Practitioners describe the stone as a modern tool for that chakra rather than an ancient one.¹⁰

Labradorite is not a birthstone for any month, according to crystal practitioners. Labradorite is sometimes called the opaline felspar because it resembles opal in its beautiful reflections of colours, a comparison made in the Illustrated catalogue of gems, cameos, & amber.¹¹⁷

What crystal practitioners say

Practitioners who work with crystals think about labradorite first as a stone for the mind. Contemporary believers consider it to enhance psychic abilities, increase intuition and bring emotional and spiritual balance. Crystal enthusiasts and energy healers regard it as valuable for its metaphysical qualities.¹²¹⁰

Widely regarded as a protective stone, labradorite is considered by practitioners to aid purification and to dispel perceived negative influences while opening the third eye. Traditionally, it is seen as a shield against outside influences that fosters inner security and confidence, and believers hold that it forms a protective barrier around the wearer.¹²¹⁰

Practitioners keep labradorite for intuition, change and protection. They lay a flat tumbled labradorite stone on the brow in meditation to work with the third eye chakra. Practitioners also keep the stone on the desk at work to hold their own mood steady and keep other people's stress from landing on them.¹¹

Practitioners say labradorite should be cleansed in moonlight, and that moonlight is the charge that fits its lore. Crystal users place labradorite under the light of the full moon overnight to charge it, as the moon's energy is believed to amplify its properties.¹¹¹⁰

Practitioners say labradorite is believed to alleviate respiratory problems such as bronchitis and asthma.¹⁰

Jewellery designers and artists describe labradorite as ideal for bold, statement jewellery and rugged pieces, and its colour flashes evoke mystery and transformation. Fetisova says that a stone's appeal to a buyer is a kind of magic that draws a person to one labradorite. Her painting technique takes advantage of labradorescence to give her paintings a dramatic effect.⁶¹³

What testing has found

Edzard Ernst, who reviewed 150 complementary and alternative treatments, found no rigorous trials that test whether crystal healing has therapeutic value. In his view, no scientific proof exists that crystal healing produces any positive effect beyond placebo.¹⁴

Christopher French's 2001 double-blind study of 80 volunteers asked people to tell real crystals from fake ones after holding them and meditating. Six people felt nothing, while the rest reported tingling or improved wellbeing, and reports were similar in the real and fake crystal groups. Participants could not tell real quartz crystals from fake glass ones, and French's researchers attributed the warmth and tingling to a placebo effect from being primed to feel them.¹⁴¹⁵¹⁶

The researchers of the 2001 study concluded that suggestion, rather than the crystals, was what helped participants. Their results have not been repeated in larger studies, which makes broad generalization difficult. Some researchers hold that crystals probably do not act directly on physical or psychological problems, though they may offer indirect benefits through the placebo effect. Few studies have compared crystal therapy with other treatments, and rigorous research remains scarce. Believers in crystal healing attribute its pleasant feelings or apparent successes to placebo effect or cognitive bias.¹⁵¹⁴

Ted Kaptchuk, a Harvard Medical School professor, said discarding placebo effects diminishes knowledge of important dimensions of health care. Kaptchuk noted that placebo effects from unconventional medicine may be dramatic and especially compelling from the patient's perspective. Edzard Ernst's source describes crystal healing as historically similar to belief in charmstones rather than based on modern scientific advances.¹⁵¹⁴