Nuummite
Orthoamphibole (Gedrite-Anthophyllite) · Semi-Precious Gemstone / Rare Mineral Specimen
Crystal System
Orthorhombic; typically found in massive, granular, or fibrous habits.
Mineral Group
Silicates; Inosilicate (Amphibole group)
Chemical Formula
(Mg,Fe)7Si8O22(OH)2
Formation Process
Metamorphic; formed under high-grade hydrothermal conditions during the Archean eon (approx. 3 billion years ago).
About This Crystal
An opaque, dark charcoal to black stone characterized by a 'labradorescent-like' schiller. It features elongated crystals or flakes with a sub-metallic to vitreous luster that flash with iridescent colors.
Physical Characteristics
Color: Black/Grey base with multi-color flashes (gold, blue, green). Streak: White to grey. Specific Gravity: 2.85–3.57. Magnetism: Usually non-magnetic but can be weakly magnetic due to iron content. Fluorescence: Generally none.
Optical Properties
Displays iridiscence or 'schiller' caused by light interference between thin lamellae of anthophyllite and gedrite. Birefringence: 0.017–0.027. Refractive Index: 1.633–1.660.
Hardness & Durability
Origin Region
Nuuk region of West Greenland (original type locale); also found in Canada and USA.
Hardness & Durability
Mohs Hardness: 5.5–6.0. Toughness: Fair to good, but susceptible to scratching compared to quartz. Stable under normal conditions but sensitive to high heat.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic cleaners and steam cleaning. Store separately to prevent scratches from harder gemstones like sapphire or topaz.
Rarity & Value
Rare. The highest quality material comes from Greenland. Value is determined by the density and variety of color flashes. It is rarely treated but sometimes imitated by 'Arfvedsonite' or 'Astrophyllite'.
Special Characteristics
Features a unique iridescent schiller that often appears as gold or copper flecks, though blue and green are also prized. It is one of the oldest volcanic rocks found on Earth.
Lore & History
Discovered in 1982 near Nuuk, Greenland. It is traditionally referred to as the 'Sorcerer's Stone' in modern crystal lore and is associated with the Root, Solar Plexus, and Third Eye chakras for protection and inner power.