Images
Formula: Na2Ca4(Ca0.5Zr0.5)Zr(Si2O7)2OF3
Sorosilicate (Si2O7 groups),
wöhlerite group,
zirconium-bearing mineral
Specific gravity: 3.25 to 3.31 measured, 3.22 calculated
Hardness: 5 to 5½
Streak: White
Colour: Yellow, yellowish brown, green
Solubility:
Common impurities: OH,Hf,Sn,Al,Y,TR,Fe,Nb,U,Mn,Mg,Sr,K
Environments
Plutonic igneous environments
Pegmatites
Metamorphic environments
Hiortdahlite is a rare mineral occurring in alkalic rocks, their
pegmatites and metamorphosed equivalents, and miarolitic
cavities in sanidine-bearing rocks.
(Webmin).
Localities
At the Hiortdahlite locality, Kipawa alkaline complex, Les Lacs-du-Témiscamingue, Témiscamingue RCM,
Abitibi-Témiscamingue, Quebec, Canada, a characteristic mode of occurrence of hiortdahlite is in streaks and
veinlets 0.5 to 4 cm wide and 10 to 20 cm in length within an alkalic
amphibolite. These veins are almost purely monomineralic but
other minerals in the amphibolite commonly include
britholite, calcite,
zircon, fluorite, and occasionally
albite and nepheline.
The hiortdahlite is colourless and clear for the most part but yellow-brown patches are observed within some
of the grains
(CM 12.241-247).
Hiortdahlite was first reported from Arøyskjærene North, Arøyskjærene, Langesundsfjorden, Larvik, Vestfold
og Telemark, Norway, where it is associated with feldspar,
biotite, meliphanite and
titanite
(HOM).
At the Korgeredaba alkaline massif, Sangilen Upland, Tuva, Russia, hiortdahlite is associated with
aegirine, astrophyllite and
nepheline
(HOM).
Back to Minerals