1.14 ct ANTIGORITE – BRAZIL

Antigorite

Antigorite is a gemstone that represents the “serpentine” soul of the deep metamorphic crust. A high-temperature member of the Serpentine group, it is a mineral I have always admired for its tough, fibrous resilience and its deep, “primeval” green hues. Unlike its softer cousin, Chrysotile, Antigorite is characterized by its compact, almost “platy” structure, which allows it to take a magnificent, waxy polish. It typically presents in shades ranging from dark forest-green to a vibrant, translucent “apple-green” known in some circles as Bowenite. For the specialist, Antigorite is a stone of the subduction zones, representing the chemical recycling of water and magnesium deep within the Earth’s mantle. It is a mineral of endurance and transformation, offering a smooth, grounding aesthetic that feels as old as the oceans.

The Heritage & Discovery

Historical Significance: Antigorite is a vital species for understanding the “serpentinization” of the Earth’s lithosphere. Historically, it has been used for millennia as a durable alternative to Jade (Nephrite) due to its toughness and beautiful translucency. In the world of fine minerals, it is celebrated for its role in creating the spectacular “Ophiolite” complexes—fragments of ancient seafloor pushed onto the continents. It stands as a symbol of protection and ancient wisdom, bridging the gap between common rock-forming silicates and the elite world of “gem-grade” ornamental stones. It serves as a reminder of the immense pressures and temperatures required to forge the green foundations of our tectonic plates.

Discovery: The mineral was first described in 1840 and was named after its type-locality in the Valle Antigorio, Piedmont, Italy. Scientifically, it is a magnesium silicate hydroxide. Its discovery provided mineralogists with the first clear look at the “lamellar” (sheet-like) structure of the serpentine minerals, distinguishing it from the fibrous varieties that form asbestos. Since its naming, it has remained the definitive representative of the high-grade serpentine family.

Important Mines: The legendary source for world-class, translucent Antigorite (variety Bowenite) is the Soochow region in China and the Mount Hope area in New Zealand. I also have a high regard for the classic, dark-green specimens from the Zermatt region in Switzerland and the historic Lizard Peninsula in Cornwall, England. For the vault, I prioritize the “Bowenite” material for its incredible, jade-like translucency and the Swiss specimens for their unmatched historical pedigree and structural purity.

Mineralogical Profile

Description: Antigorite is a magnesium silicate hydroxide that crystallizes in the monoclinic system. It sits at a 3.5 to 4 on the Mohs scale, though its interlocking “felted” structure makes it surprisingly tough and resistant to breaking. It is characterized by its waxy to greasy luster and its range of dark green, bluish-green, and occasionally yellow-green colors.

One of its most identifying traits is its lamellar habit—it forms in thin, overlapping plates that are often curved or corrugated on a microscopic scale. It has a moderate refractive index (approx 1.56 to 1.57) and a characteristic “greasy” feel in the hand. Because it is a phyllosilicate (sheet silicate), it is often associated with Talc, Magnetite, and Chromite. When I select a piece for the collection, I look for a “vibrant” green translucency and a high-gloss waxy finish, as these represent the species in its most aesthetic and desirable form. It is a dense, high-vibration mineral that offers a unique, “organic” depth unlike any other silicate species.

Chemical Formula: (Mg,Fe²⁺)₃Si₂O₅(OH)₄