Howlite
Howlite (Calcium Borosilicate Hydroxide) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Monoclinic; crystals are extremely rare, typically found in massive, nodular, or cauliflower-like habits.
Mineral Group
Borates (Nesoborates)
Chemical Formula
Ca2B5SiO9(OH)5
Formation Process
Evaporite mineral typically found in sedimentary continental basins, formed through the precipitation of boron-rich fluids.
About This Crystal
An opaque, white to milky grey mineral with a sub-vitreous to earthy luster. It is highly distinctive for its irregular, web-like veins of dark grey, black, or brown matrix (often composed of other minerals like Quartz or Carbonates).
Physical Characteristics
Color: White with grey veining; Streak: White; Cleavage: None visible in massive form; Fracture: Conchoidal to even; Specific Gravity: 2.45–2.58; Fluorescence: Sometimes fluoresces brownish-yellow or orange under shortwave UV.
Optical Properties
Opaque in massive form; Refractive Index is approximately 1.583–1.605; Biaxial negative; No pleochroism or dispersion effects visible in polished stones.
Hardness & Durability
Origin Region
Primarily Tick Canyon, California, USA; Nova Scotia, Canada; and parts of Mexico and Turkey.
Hardness & Durability
Mohs Hardness: 3.5. It is a relatively soft stone, easily scratched by many household objects and harder gemstones; poor toughness due to porosity.
Care & Maintenance
Should be cleaned only with warm soapy water and a soft cloth; avoid ultrasonic cleaners, steam, and acidic chemicals. Porous nature allows it to absorb oils and dyes easily.
Rarity & Value
Relatively common and inexpensive. Its value is often increased when used as a simulant for Turquoise (dyed blue) or White Buffalo Stone. Prices for tumbled stones are generally very low.
Special Characteristics
Highly porous structure makes it the primary material used for 'Magnesite' or 'Turquenite' imitations through dyeing. Natural specimens are valued for their 'spider-web' matrix patterns.
Lore & History
Named after Henry How, who first described it in 1868 in Nova Scotia. In metaphysical traditions, it is known as a 'calming stone' used to relieve stress and insomnia, often associated with the Crown Chakra.