01Decisive
Cut a drill hole edge with a knife
Howlite at 3.5 gives way immediately and produces white powder. Turquoise at 5–6 does not. White powder under a blue surface settles the question with no ambiguity at all.
Turquoise · Lovenhall Stone
How to Identify Dyed Howlite
White mineral with grey veins, dyed blue. The single commonest turquoise simulant.
Iran, the American Southwest, China, Egypt, Mexico2 references
Howlite is a calcium borosilicate that occurs as white to grey nodules with dark grey-brown veining, and its natural appearance is startlingly close to the structure of webbed turquoise minus the colour. Dye supplies the colour, and the result passes at arm's length.
Two properties give it away and neither takes equipment. It is hardness 3.5, so a steel knife cuts it easily and even a copper coin will mark it, where turquoise at 5–6 resists both. And it is white beneath the dye, so any chip, scratch or drill hole exposes white or pale material under a blue skin.
The veining pattern is the third tell and the most visible without touching the stone. In dyed howlite the veins are more porous than the body, so they take up more dye and read as darker blue lines. In natural turquoise the veining is host rock — limonite, quartz or black chert — and is brown, rust or black, never a deeper shade of the same blue.
Undyed howlite is also sold honestly as 'white turquoise', which is a marketing name rather than a mineral one. And a good deal of material sold as 'white buffalo turquoise' is howlite or magnesite; the genuine white buffalo stone from Nevada is a real and separate material, which is precisely why the name is borrowed.
References and sizes
'White turquoise' (undyed howlite) · 'White buffalo' (usually howlite or magnesite)
Establish which of these you are holding before judging it. A genuine piece read against another reference's rules will look wrong when it is not.
Model-specific checks
What decides a Dyed Howlite
These apply to this model and not to the rest of Turquoise. Work them alongside the maker's general checks, not instead of them.
02Decisive
Compare vein colour against body colour
Dyed howlite's veins are darker blue than its body because they absorbed more dye. Natural turquoise's veins are brown, rust or black host rock. A bluer vein is dye, every time.
03Strong
Look into the drill hole of a bead
Dye penetrates from the outside, so a drilled bead often shows a blue rind and a pale core where the dye did not reach. Natural turquoise is the same colour through the bead.
The market
What a Dyed Howlite does on the secondary market
A few dollars for a whole strand of beads. As turquoise it is worthless; as howlite it is an honest cheap stone.
An orientation for honest, unrestored condition — never an appraisal, and never a quotation.
Questions we are asked
- How can I tell dyed howlite from turquoise?
- Hardness and veining. Howlite is 3.5 on the Mohs scale, so a steel knife cuts it and produces white powder; turquoise is 5–6 and resists. And dyed howlite's veins read as darker blue than its body because they absorbed more dye, whereas natural turquoise's veins are brown, rust or black host rock.
- Is white turquoise real turquoise?
- Usually not. 'White turquoise' is generally undyed howlite or magnesite sold under a marketing name. Turquoise gets its colour from copper, so a genuinely white stone is chemically unlikely to be turquoise.
All the Turquoise checks
Free tools of the room
Lovenhall StoneRead the stone itself
The tests tell you what it is. The instrument reads a photograph and offers a name to start from — then hands you back to the tile and the coin, which are what settle it.
Free on iPhone & iPad. An estimate, never an appraisal.
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