Garnet: meaning, properties and lore

The mineral

Garnet is a group of minerals rather than a single species. All garnets have essentially the same crystal structure but vary in chemical composition, and many garnets are chemical mixtures of two or more garnet species.¹³⁷

More than twenty garnet species exist, and five are commercially important as gems: pyrope, almandine, spessartine, grossular and andradite. Demantoid is a brilliant green variety of andradite, while tsavorite and hessonite are grossular varieties, and uvarovite usually forms crystals too small to cut.¹²⁵⁸

Chemically, garnet is a double silicate of alumina and lime, coloured with iron and manganese. Spessartine has the chemical formula Mn₃Al₂(SiO₄)₃. Garnet has a specific gravity of 3.47-4.15 and a refractive index of 1.714-1.888 with no birefringence.⁶³

Garnet is often thought of as a deep red gemstone but can also be yellow, orange, green or brown, in any colour except blue. Red garnet is one of the most common and widespread gems, while spessartine is an orange garnet and rhodolite is a purple-red garnet. Some garnets can exhibit a colour-change phenomenon similar to alexandrite, and some change colour under different types of lighting.⁵¹⁷²⁸

Garnet has a Mohs hardness of 6.5-7.5. Almandine, pyrope, spessartine and tsavorite are on the harder side of garnet hardness, while demantoid is a bit softer. Garnets have fair to good toughness and are stable to light and chemicals, but hydrofluoric acid can attack them.³⁴²

Garnets sometimes show asterism, a star-shaped pattern of reflections, and chatoyancy, a cat's-eye effect seen in reflected light. Grossular is typically translucent. Garnets might rarely be treated by fracture filling.⁵⁸⁴²

Garnet occurs in metamorphic rocks on every continent, and tsavorite also forms in metamorphic rocks but is rarer because it needs unusual rock chemistries and special conditions. Campbell Bridges mined tsavorite garnet in Kenya near Tsavo National Park. Namibia is now producing demantoids, and most bright green tsavorites on the market come from Kenya, Tanzania and Madagascar. Garnet is also found in Myanmar, Brazil, Iran, Afghanistan, Pakistan, India and Sri Lanka. Bohemia, now part of the Czech Republic, was the primary source of red pyrope garnets popular in Victorian times.¹⁷³²

History and lore

The name garnet originates from the medieval Latin granatus, meaning pomegranate, in reference to the similarity of the red colour. The root of pyrope is pyro, the Greek word for fire.²⁷

Garnets have been used since the Bronze Age as gemstones and abrasives, and necklaces studded with red garnets adorned the pharaohs of ancient Egypt. Red garnet necklaces were entombed with mummified pharaohs as prized possessions for the afterlife. A red garnet bead necklace found in a grave in Egypt is more than 5,000 years old.²⁹⁷³

In ancient Rome, signet rings with carved garnets were used to stamp the wax that secured important documents. In Pliny's time (23 to 79 AD), red garnets were among the most widely traded gems. The term carbuncle was often used in ancient times to refer to red garnets, although it was used for almost any red stone.⁹

Carbuncle was thought to be one of the four precious stones given to King Solomon by God. In the Middle Ages red garnet was favored by clergy and nobility.⁹

Red garnet's availability increased with the discovery of the famous Bohemian garnet deposits in central Europe around 1500. The Bohemian garnet deposits became the nucleus of a regional jewelry industry that reached its peak in the late 1800s. The imperial Russian jeweler Fabergé created intricate jewelry designs for demantoid garnet.⁹³

In ancient and medieval times, garnet was thought to be a remedy for inflammatory diseases and to soothe the angry heart. Dr. Edward Gübelin's lifelong study of gems and their inclusions revolutionized the science of gemology.²⁵

Birthstone and other links

Garnet is the January birthstone, as the Gemological Institute of America presents it on its birthstone page. Garnet is also the gem for the second anniversary.¹³

Crystal practitioners say garnet is closely associated with January birthdays and has been a favored birthstone for centuries. The link to January is a modern practitioner association rather than a list from the ancient period.

What crystal practitioners say

Crystal healers hold that garnet is associated with emotional stability and grounding. They say it accompanies the release of fear, anger or discouragement.²

The Healing Crystals First Aid Book says garnet pyrope is said to help maintain a positive attitude in difficult times. The same book says it is said to mobilise energy reserves against exhaustion. It also says garnet pyrope is said to help overcome resistance emotionally and assist perseverance.¹⁰

Crystal practitioners associate garnet pyrope with physical use. The Healing Crystals First Aid Book says it is said to be used by placing a crystal over the pubic bone, or wearing it as a pendant.¹⁰

Crystal practitioners treat garnets with care, handling them gently and keeping them away from harsh chemicals.⁴

What testing has found

Edzard Ernst, in his analysis of 150 complementary and alternative treatments, concluded that rigorous trials testing the therapeutic value of crystal healing do not exist. Ernst also noted that French's study did not test that value, so his earlier statement is not entirely false. In his view, no scientific proof exists of any positive effect beyond a placebo effect for crystal healing.¹¹

Six people felt nothing at all, while the rest reported some energy such as tingling or an improved sense of wellbeing. Participants holding fake and real crystals reported similar impressions, suggesting the placebo effect could be at play.¹¹

French and his team found that crystals did not help people, and that the power of suggestion was responsible for any effect people felt. Some researchers believe crystals probably do not act directly on physical or psychological complaints, though they may offer indirect benefits linked to the placebo effect.¹²

Ted Kaptchuk, a Harvard Medical School professor, says discarding placebo effects diminishes knowledge of important dimensions of health care. Kaptchuk says some unconventional medicine may produce placebo outcomes that are dramatic and especially compelling from the patient's perspective.¹²