3358 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
MINERALOGY
The pegmatites show marked mineralogical and chemical
diversity, with more than eighty mineral species, including
rock-forming albite, quartz, microcline, and muscovite, as
well as less abundant apatite, tourmaline, fluorite, and cal-
cite. The mineral assemblages in some deposits are albite,
cleavelandite, lepidolite, pollucite, spodumene, petalite,
amblygonite, polychrome tourmaline, beryl, tantalite-
columbite, cassiterite, etc.
The main ore minerals are tantalite-columbite, cassiter-
ite, spodumene, pollucite, and beryl. Oligoclase-microcline
assemblage: quartz, oligoclase, microcline, silver-white
muscovite, prismatic black tourmaline (schorl), red or pur-
ple tetragon-trioctahedral, or less often rhombic dodecahe-
dral garnet crystals, and occasionally albite. The assemblage
is predominant in barren pegmatite veins with aplite and
aplite-pegmatite selvages and fine quartz-microcline-
muscovite aggregates in the axes. Microcline assemblage:
fragmentary quartz-microcline blocks in large pegma-
tite veins, with coarse isometric crystals of microcline or
their aggregates, as well as nests of coarse silver-white flaky
muscovite, greenish-grey beryl, and columbite muscovite
contains relatively high amounts of tantalum, niobium,
beryllium and tin, and rare alkalis (Li +Rb +Cs =1.5–2%).
The mineralization zoning in veins reveals the following for-
mation sequence of mineral assemblages: oligoclase-micro-
cline pegmatite (barren) → microcline-quartz-muscovite
(Nb, Be) → microcline-albite (Ta, Sn, Be) → albite (Ta,
Nb, Be, Sn) → quartz-mica and albite-spodumene (Li, Ta,
Be, Sn) → cleavelandite-lepidolite-pollucite-spodumene
(Ta, Li, Cs, Sn).
Taylor (2005) describes the tantalum mineralisation in
pegmatite dykes in Ontario, Canada, (Tables 1–3).
No modern mineralogy is available for historical work
on LPPO deposits but this could be incorporated into any
new drilling to be undertaken in the future. QEMSCAN is
a typical and very informative analytical technique regard-
ing the nature, occurrence and liberation size of the min-
erals present. QEMSCAN employs a scanning electron
microscope, four X-ray detectors and a software package
which enables rapid discrimination of minerals, without
Table 1. Lithium bearing minerals
Mineral Composition Content, %Density, g/cm3 Hardness, Mohs
Spodumene LiAl [Si
2 O
6 ]8.03 3.2 6.5–7.0
Lepidolite K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2 5.9 2.8–2.9 2.0–3.0
Amblygonite LiAl (PO4) (FOH) Li2O3 ·2LiFP2O5 ·Li2O 10.10 3.0–3.2 6.0
Zinnwaldite KLiFeAl [Si
3 AlO
10 ][FOH]
2 4.13 2.90–3.20 2.0–3.0
Petalite (LiNa) [AlSi
4 O
11 ]4.89 2.39–2.46 6.0–6.5
Eucryptite LiAlSiO4 11.9 2.67 6.5
Table 2. Berylium bearing minerals
Mineral Composition Be Content, %Density, g/cm3 Hardness, Mohs
Beryl Be3Al2 (Si6O18) 5.03 2.60–2.90 7.5–8.0
Bertrandite Be
4 (Si
2 O
7 )(OH)
2 15.13 2.60 6.0
Xrizoberyl Al
2 BeO
4 7.09 3.50–3.80 8.5
Phenacite BeO2 (SiO4) 6.77 3.00 7.5
Gelvin Mn8 (BeSiO4)6S2 4.86 3.30 6.0–6.6
Getgelvin Zn
8 (BeSiO
4 )
6 S
2 4.54 3.66 —
Danolit Fe
8 (BeSiO
4 )S
2 1.47 3.40 5.5–6
Table 3. Tantalum and niobium minerals
Mineral Composition Density, g/cm3 Hardness, Mohs
Tantalite (Fe, Mn) Ta2O6 6.25–7.90 6.5
Columbite (Fe, Mn) Nb2O6 5.00 6.0
Ferrotapiolite (Fe, Mn) (Ta, Nb)
2 O
6 5.00–7.90 6.0–6.5
Quartz SiO
2 2.65 7.0
Plagioclase Na [AlSi3O8]-Ca [Al2Si2O8] 2.61–2.76 6.0–6.5
Albite Na2O·Al2O3·6SiO2 2.62 6.0–6.5
Muscovite KAl
2 [AlSi
3 O
10 ][OH]
2 2.77–2.88 2.5–4.0
MINERALOGY
The pegmatites show marked mineralogical and chemical
diversity, with more than eighty mineral species, including
rock-forming albite, quartz, microcline, and muscovite, as
well as less abundant apatite, tourmaline, fluorite, and cal-
cite. The mineral assemblages in some deposits are albite,
cleavelandite, lepidolite, pollucite, spodumene, petalite,
amblygonite, polychrome tourmaline, beryl, tantalite-
columbite, cassiterite, etc.
The main ore minerals are tantalite-columbite, cassiter-
ite, spodumene, pollucite, and beryl. Oligoclase-microcline
assemblage: quartz, oligoclase, microcline, silver-white
muscovite, prismatic black tourmaline (schorl), red or pur-
ple tetragon-trioctahedral, or less often rhombic dodecahe-
dral garnet crystals, and occasionally albite. The assemblage
is predominant in barren pegmatite veins with aplite and
aplite-pegmatite selvages and fine quartz-microcline-
muscovite aggregates in the axes. Microcline assemblage:
fragmentary quartz-microcline blocks in large pegma-
tite veins, with coarse isometric crystals of microcline or
their aggregates, as well as nests of coarse silver-white flaky
muscovite, greenish-grey beryl, and columbite muscovite
contains relatively high amounts of tantalum, niobium,
beryllium and tin, and rare alkalis (Li +Rb +Cs =1.5–2%).
The mineralization zoning in veins reveals the following for-
mation sequence of mineral assemblages: oligoclase-micro-
cline pegmatite (barren) → microcline-quartz-muscovite
(Nb, Be) → microcline-albite (Ta, Sn, Be) → albite (Ta,
Nb, Be, Sn) → quartz-mica and albite-spodumene (Li, Ta,
Be, Sn) → cleavelandite-lepidolite-pollucite-spodumene
(Ta, Li, Cs, Sn).
Taylor (2005) describes the tantalum mineralisation in
pegmatite dykes in Ontario, Canada, (Tables 1–3).
No modern mineralogy is available for historical work
on LPPO deposits but this could be incorporated into any
new drilling to be undertaken in the future. QEMSCAN is
a typical and very informative analytical technique regard-
ing the nature, occurrence and liberation size of the min-
erals present. QEMSCAN employs a scanning electron
microscope, four X-ray detectors and a software package
which enables rapid discrimination of minerals, without
Table 1. Lithium bearing minerals
Mineral Composition Content, %Density, g/cm3 Hardness, Mohs
Spodumene LiAl [Si
2 O
6 ]8.03 3.2 6.5–7.0
Lepidolite K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2 5.9 2.8–2.9 2.0–3.0
Amblygonite LiAl (PO4) (FOH) Li2O3 ·2LiFP2O5 ·Li2O 10.10 3.0–3.2 6.0
Zinnwaldite KLiFeAl [Si
3 AlO
10 ][FOH]
2 4.13 2.90–3.20 2.0–3.0
Petalite (LiNa) [AlSi
4 O
11 ]4.89 2.39–2.46 6.0–6.5
Eucryptite LiAlSiO4 11.9 2.67 6.5
Table 2. Berylium bearing minerals
Mineral Composition Be Content, %Density, g/cm3 Hardness, Mohs
Beryl Be3Al2 (Si6O18) 5.03 2.60–2.90 7.5–8.0
Bertrandite Be
4 (Si
2 O
7 )(OH)
2 15.13 2.60 6.0
Xrizoberyl Al
2 BeO
4 7.09 3.50–3.80 8.5
Phenacite BeO2 (SiO4) 6.77 3.00 7.5
Gelvin Mn8 (BeSiO4)6S2 4.86 3.30 6.0–6.6
Getgelvin Zn
8 (BeSiO
4 )
6 S
2 4.54 3.66 —
Danolit Fe
8 (BeSiO
4 )S
2 1.47 3.40 5.5–6
Table 3. Tantalum and niobium minerals
Mineral Composition Density, g/cm3 Hardness, Mohs
Tantalite (Fe, Mn) Ta2O6 6.25–7.90 6.5
Columbite (Fe, Mn) Nb2O6 5.00 6.0
Ferrotapiolite (Fe, Mn) (Ta, Nb)
2 O
6 5.00–7.90 6.0–6.5
Quartz SiO
2 2.65 7.0
Plagioclase Na [AlSi3O8]-Ca [Al2Si2O8] 2.61–2.76 6.0–6.5
Albite Na2O·Al2O3·6SiO2 2.62 6.0–6.5
Muscovite KAl
2 [AlSi
3 O
10 ][OH]
2 2.77–2.88 2.5–4.0