Gem library
Howlite
White veined with black, queen of imitations
Howlite is a white borate crossed by cobweb-like black veins. Little known under its true name, it is nonetheless everywhere: dyed blue, it is the world's most widespread turquoise imitation, and dyed purple, the fake «turquenite» or «lapis».
- Hardness (Mohs)
- 3.5
- Density
- 2.53 – 2.59
- Crystal system
- Monoclinic
- Refractive index
- 1.583 – 1.608
- Cleavage
- None
Mineralogical identity
- Family
- Borates
- Species
- Howlite
- Chemical formula
- Ca₂B₅SiO₉(OH)₅
- Crystal system
- Monoclinic
- Classification
- Semi-precious stone (rock)
- Rarity
- Very common
- Indicative price
- €0.10 – 1/ct
Etymology
Named after Henry How, the Canadian chemist and geologist who described it in Nova Scotia in 1868.
Physical & optical properties
- Hardness (Mohs)
- 3.5
- Density
- 2.53 – 2.59
- Refractive index
- 1.583 – 1.608
- Birefringence
- 0.022
- Cleavage
- None
- Fracture
- Splintery
- Lustre
- Dull to subvitreous
- Diaphaneity
- Opaque
- UV fluorescence
- Weak
- Pleochroism
- None
- Colours
- white, white veined with black, grey
Formation, geology & history
An evaporite borate
Howlite forms in borate deposits of evaporitic origin: ancient dried-up salt lakes where circulating boron-rich brines precipitated a series of minerals — borax, ulexite, colemanite, howlite. The Californian deposits of the Mojave Desert, worked for industrial borax, supply most of it as a by-product. It occurs as compact white nodules of chalky appearance, crossed by black or grey veins that are in fact inclusions of clay and oxides. Those fine, regular veins in a cobweb network are its signature — and paradoxically its resemblance to turquoise matrix, which made its commercial fortune.
The great imitator
White, porous and soft, howlite takes dye with remarkable ease. Dyed blue it imitates turquoise; deep blue, lapis lazuli; green, malachite or chrysoprase; purple, a supposed «turquenite» or «purple moonstone»; pink, rhodochrosite. It is found under dozens of fanciful trade names. Spotting it is simple, however: its hardness of 3.5 means a knife — sometimes a fingernail — scratches it, its density is low, and cotton soaked in acetone rubbed on a discreet spot lifts dye. Its black veins are also too fine and too regular compared with the irregular matrix of real turquoise.
A stone in its own right
In its natural form, milky white veined with grey, howlite has a sober charm and serves for cabochons, beads and pebbles. It is very affordable and easy to work, provided its softness is respected. One close cousin deserves mention: ulexite, the «television stone», whose parallel fibres transmit an image of whatever lies beneath the stone to its upper surface — a spectacular natural fibre-optic effect, often sold beside howlite in the same shops.
How to recognise it
- Very fine, regular black veinsThe black cobweb network on a chalky white ground is the howlite signature. Real turquoise matrix is brown or ochre and far more irregular.
- Hardness 3.5It is scratched by a knife without effort and sometimes by a fingernail on softer zones. Turquoise (5-6) resists a knife.
- Chalky matt appearanceEven polished, howlite keeps a slightly matt, milky finish, less waxy than turquoise.
Imitations, treatments & confusions
- It is the imitation, not the imitatedA special case: howlite is the main simulant of turquoise, lapis, malachite and rhodochrosite. So the reflex is the opposite — suspect howlite behind any coloured stone that is too soft.
- MagnesiteOften confused with howlite and used for the same imitations. It fizzes in vinegar (a carbonate); howlite does not.
- Reconstituted resinVein patterns too regular, lightness, plastic smell on a hot point.
Deposits & origins
Canada (Nova Scotia, type locality), United States (California: Tick Canyon, Death Valley — the main source of ornamental material), Mexico, Serbia, Turkey, Russia
Care & precautions
- Brief rinsing in warm water, dried at once. Porous, it absorbs liquids and stains.
- On dyed pieces, absolutely avoid hot water, alcohol and acetone: the dye comes away.
- Very soft: it is scratched by contact with other jewellery and with keys. Individual storage.
- No ultrasonic cleaning or steam; no household products or perfumes.
Traditions & crystal healing
- Chakras
- Crown · third eye
- Zodiac signs
- Gemini · Virgo
- Element
- Air
Contemporary tradition makes it a stone of mental calm and sleep, often placed under the pillow to quiet rumination. Its milky white is associated with clarity and neutrality. This is a recent use: howlite was only described in 1868 and therefore has no ancient tradition.
The virtues described here belong to tradition and cultural heritage. They are in no way medical advice and never replace a consultation.
Frequently asked questions
Is my turquoise actually howlite?
Check three points: hardness (howlite is scratched by a knife), veins (black and cobweb-like in howlite, brown and irregular in turquoise), and dye deposit on cotton soaked in acetone.
Does howlite have any value?
Very little as a material, but it has its own charm in natural white veined form. The problem is not the stone, it is its sale under a false identity.
Howlite or magnesite?
One test is enough: magnesite is a carbonate and fizzes in vinegar; howlite is a borate and does not react. Both serve the same imitations.