Howlite
Howlite · Semi-Precious Gemstone and Decorative Stone
Crystal System
Monoclinic; typically occurs as massive nodules, tuberous aggregates, or microcrystalline veins, rarely forming distinct tabular crystals.
Mineral Group
Borates
Chemical Formula
Ca2B5SiO9(OH)5
Formation Process
Sedimentary formation through chemical precipitation in evaporating borate lakes and basins under arid or semi-arid conditions.
About This Crystal
An opaque, chalky-to-vitreous white or milky mineral heavily patterned with a dense web of dark grey, black, or brown fine matrix veins, giving it a marble-like appearance.
Physical Characteristics
White body color with grey to black veining; white streak; sub-conchoidal to uneven fracture; cleavage is absent; specific gravity is approximately 2.53 to 2.59; brittle tenacity; exhibits faint yellow or yellowish-white fluorescence under UV light.
Optical Properties
Biaxial positive optical sign with refractive indices around 1.583 to 1.605; low birefringence; completely opaque to translucent in thin edges; no pleochroism.
Hardness & Durability
Origin Region
Nova Scotia (Canada), California (USA), Germany, and South Africa. Typically forms in evaporite deposits and borate-rich lacustrine environments.
Hardness & Durability
Mohs hardness of 3.5; relatively soft and easily scratched by a copper coin or knife; poor wearability for rings or daily-wear jewelry unless protected by bezels; low toughness due to porous nature.
Care & Maintenance
Clean gently with warm, soapy water and a soft cloth; avoid harsh chemical cleaners, prolonged exposure to water (due to slight porosity), and ultrasonic or steam cleaners; store separately from harder stones to avoid scratching.
Rarity & Value
Common and widely accessible; inexpensive, typically valued as an affordable decorative stone, carving material, or bead; frequently dyed blue to imitate turquoise (known commercially as turquenite).
Special Characteristics
Highly porous structure which readily absorbs liquid dyes, making it one of the most common stones used for imitation turquoise; features distinctive dark web-like matrix patterns.
Lore & History
Discovered in Nova Scotia in 1868 by Henry How, a Canadian chemist and geologist. Often associated in modern crystal healing traditions with stress relief, calming an overactive mind, patience, and emotional healing, though these are traditional cultural beliefs rather than scientifically verified properties.