Mineral - Atencioite
Atencioite
Chemical Properties
Mineral Class
Phosphates
Toxicity
none
Formula
Ca₂Fe²⁺₃Mg₂Be₄(PO₄)₆(OH)₄ · 6H₂O
Unit Cell
a=6.79 b=9.97 c=10.01 α=74° β=85° γ=87° Z=1
Physical Properties
Hardness
4.5
Streak
white
Density
Normal (2-3,5)
Cleavage
Fracture
uneven
Tenacity
Brittle
Optical Properties
Color
brownyellowgreengreen grey
Birefringence
0,013
Luster
Vitreous,
Earthy,
Waxy
Transparency
translucent,
opaque
Pleochroism
X: Grün
Y: Grün-Braun
Geomineralogical Properties
Crystal System
triclinic
Point Group
triclinic-pinacoidal - 1
Space Group
P 1 (2)
Habit
spherical, tabular
Formation
Secondary in magmatic pegmatites, formed from primary phosphates
Paragenesis
Twinning
Rarity
Rare
Synonyms
Atencioite
Composition
Elements
Mass
BeO
9.28
MgO
7.47
CaO
10.40
FeO
19.99
P₂O₅
39.49
H₂O
13.37
Brazil (Chukanov et al. unp.)
Groups and Members
Roscherite-Group
Name and first discovery : Named after the Brazilian mineralogist Prof. Dr. Daniel Atencio (1960). First documented in 2004.
Chemistry :
Synonyms :
Varieties :
Abbreviation : Aco
literature
Chukanov, NV, Rastsvetaeva, RK, Möckel, S., Zadov, AE, & Levitskaya, LA THE ROSCHERITE GROUP AND ITS NEW REPRESENTATIVE ATENCIOITE, Ca 2 Fe 2 Mg 2 Fe 2 Be 4 (PО 4) 6 (OH) 4· 6H 2 O.