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Lepidolite
Chemistry
Chemistry available on new site, see link above
Links to Other Materials
- Amblygonite - Related
- Petalite - Related
- Spodumene - Related
- PEGMATITE - Related
- Cache
Miscellaneous
- Family: Feldspar
- Region: North America
- Mined At: Unspecified
- Raw Mineral: Yes
- Generic: Yes
Notes
Although this material is sometimes referred to as a lithium feldspar, it is not a feldspar, but rather a lithium mica. A natural source of Li2O, usually about 5%. It is a raw material for the production of lithium carbonate.
Like other feldspars, it softens over a range (1150-1300C). It has a lower fusion point than most high temperature feldspars.
The fluorine content can cause problems with glaze bubbles and surface pitting.
Its ideal formula is LiF.KF.Al2O3.3SiO2.
However it is tricky to establish a formula weight and analysis for this material. Here are some of the factors:
-LOI varies, but we have assumed 5% water in this example.
-Lepidolite does not actually contain Li2O, it has to absorb oxygen from the atmosphere or other materials during firing since the Li is bonded to F.
-Fluorine is bonded to potassium so oxygen has to be absorbed to create K2O.
-For both Li and K only 1/2 of a molecule per input molecule of lepidolite will be yeilded.
-In a complete oxidation firing all of the fluorine will volatilize and none will be in the final glass. However in real world conditions none of these is likely to happen completely, and in a reduction firing none may happen at all. In this case we are assuming it is all LOI.
Given the above assumptions, an input of LiF.KF.Al2O3.3SiO2 would yield:
1/2 Li2O
1/2 K2O
2 F
1 Al2O3
3 SiO2
5 LOI
Considering the F as LOI we would have:
3% Li2O
7.3% K2O
26.9% Al2O3
47.7% SiO2
15% LOI
To properly handle a material like this in ceramic calculations fluorine conversion factors have to be employed.
(Richard Willis)
Mineral, of the ideal form K(Li, Al)3[(OH, F)2(AlSi4O10)] , of a complex and variable empirical composition.
Hardness: 2.5-3 Density: 2.8-2.9 Soluble in acids
Important lithium ore. see spodumene
Data
- Melting Point (MP): 1200C
- Specific Gravity: 3.00
- Specific Gravity: 3.00
- Melting Point (MP): 1200C
URLs
- Mineral information - http://mineral.galleries.com/minerals/silicate/lepidoli/lepidoli.htm
- More mineral information - http://webmineral.com/data/Lepidolite.shtml
- More mineral information - http://www.mindat.org/show.php?name=Lepidolite
- Wikipedia definition - http://en.wikipedia.org/wiki/Lepidolite
Suppliers
- Generic
Authors
- Tony Hansen (Owner)
Pictures
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Lepidolite
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Lepidolite Stone
XML
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