Mineral - Aheylite
Aheylite
Chemical Properties
Mineral Class
Phosphates
Toxicity
none
Formula
(Fe²⁺,Zn)Al₆(PO₄)₄(OH)₈ · 4H₂O
Unit Cell
a=7.40 b=9.90 c=7.63 α=111° β=115° γ=70° Z=1
Physical Properties
Hardness
5 - 5.5
Streak
green
Density
Normal (2-3,5)
Cleavage
Fracture
hooked,
splintery
Tenacity
Optical Properties
Color
greenblue
Birefringence
Luster
Vitreous
Transparency
translucent,
transparent,
opaque
Pleochroism
Geomineralogical Properties
Crystal System
triclinic
Point Group
triclinic-pinacoidal - 1
Space Group
P 1 (2)
Habit
spherical
Formation
Formed as a secondary mineral through the hydrothermal alteration of variscite-like phosphates or through the supergene alteration of primary ore minerals within the oxidation zone of tin-sulfide deposits
Paragenesis
Twinning
Rarity
Very rare
Synonyms
Aheylite
Composition
Elements
Mass
P₂O₅
35.40
Al₂O₃
38.10
FeO
4.14
ZnO
4.02
H₂O
18.50
Bolivia (Foord & Taggart 1998)
Groups and Members
Turquoise-Group
Name and first discovery : Named after the American geologist Allen V. Heyl (1918-2008). Discovered in Bolivia in 1984.
Chemistry :
Synonyms :
Varieties :
Abbreviation : Ahe
literature
Foord, E. E., & Taggart, J. E. (1998). A reexamination of the turquoise group: the mineral aheylite, planerite (redefined), turquoise and coeruleolactite. Mineralogical Magazine , 62 (1), 93-111.