Mineral - Almeidaite
Almeidaite
Chemical Properties
Mineral Class
Oxides and Hydrxides
Toxicity
none
Formula
PbZn₂(Mn,Y)(Ti,Fe³⁺)₁₈O₃₇(OH,O)
Unit Cell
a=10.44 c=21.05 Z=3
Physical Properties
Hardness
6
Streak
brown
Density
Heavy (3,5-6)
Cleavage
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
blackgraysilver
Birefringence
Luster
Metallic
Transparency
opaque
Pleochroism
Geomineralogical Properties
Crystal System
trigonal
Point Group
rhombohedral - 3
Space Group
R 3 (148)
Habit
coarse, massive, tabular
Formation
Igneous
Paragenesis
Twinning
Rarity
Rare
Synonyms
Almeidaite
Composition
Elements
Mass
CaO
0.12
SrO
0.69
PbO
7.13
MnO
2.64
ZnO
6.26
Fe₂O₃
22.83
Y₂O₃
2.81
La₂O₃
0.25
TiO₂
56.10
H₂O
0.40
Brazil (Menezes et al. 2015)
Groups and Members
Crichtonite-Group
Name and first discovery : Named after Brazilian geologist Fernando Flávio Marques de Almeida (1916-2013). Almeidaite was discovered in 2013 in an unnamed locality in Novo Horizonte, Brazil.
Chemistry :
Synonyms :
Varieties :
Abbreviation : Amd
literature
Menezes Filho, LA, Chukanov, NV, Rastsvetaeva, RK, Aksenov, SM, Pekov, IV, Chaves, ML, ... & Ardisson, JD (2015). Almeidaite, Pb (Mn, Y) Zn2 (Ti, Fe3+) 18O36 (O, OH) 2, a new crichtonite-group mineral, from Novo Horizonte, Bahia, Brazil. Mineralogical Magazine , 79 (2), 269-283.