Howlite
Howlite · Semi-Precious Gemstone / Decorative Stone
Crystal System
Monoclinic; typically found in massive, nodular, or cauliflower-like habits; crystals are extremely rare.
Mineral Group
Borates (Nesoborate)
Chemical Formula
Ca2B5SiO9(OH)5
Formation Process
Formed in evaporite deposits within continental basins, typically as a result of boron-enriched fluids reacting with calcium-rich sediments.
About This Crystal
An opaque, milky white to grey stone featuring a sub-vitreous to earthy luster. It is characterized by distinctive dendritic veining patterns of dark grey, black, or brown running through the matrix.
Physical Characteristics
Color: White to light grey with dark veins; Streak: White; Cleavage: None (massive form); Fracture: Conchoidal to even; Specific Gravity: 2.45–2.58; Fluorescence: Occasionally blue, yellowish, or orange under shortwave UV.
Optical Properties
Refractive Index: 1.583–1.605; Birefringence: 0.022; Opaque; No distinctive optical phenomena like chatoyancy or asterism.
Hardness & Durability
Origin Region
Nova Scotia (Canada), California (USA), Mexico, Turkey, Germany.
Hardness & Durability
Mohs Hardness: 3.5; Brittle toughness. Low durability for rings; better suited for pendants, earrings, or decorative beads.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic cleaners and steam. Highly porous and sensitive to acids and household chemicals. Should be stored separately from harder gemstones to prevent scratching.
Rarity & Value
Common and affordable. Value is determined by the aesthetics of the veining. Frequently used as a 'simulant' because it is porous and dyes easily to imitate Turquoise or Lapis Lazuli.
Special Characteristics
Highly porous structure allows it to take dye exceptionally well; often sold as 'Turquenite' when dyed blue.
Lore & History
Discovered by Henry How in 1868. In metaphysical traditions, it is known as the 'calming stone,' associated with the Crown Chakra and believed to aid insomnia and reduce anger/stress.