Definition
The empirical formula is derived from the mineral's structural (molecular)
formula by using the published analysis of the mineral or deriving the analysis
using basic rules.
- Atomic substitutions were analyzed by the following procedure if published
analyses were not available. Adjustments were made to match the measured
density with the calculated density if needed:
(K,Na) = K0.75 Na0.25
(K,Na,Cs)= K0.6 Na0.3 Cs0.1
- Rare Earth Elements (REE in formulae) were calculated based on the
chondrite normalized abundances. This database used 144 for the REE atomic
weight and 61 as the atomic number.
- Solid solution series minerals were calculated based on the mid-points of
the accepted compositional range of the mineral.
The empirical formula was used to calculate the chemical composition in this
database.
Other References to Empirical Formula
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Example Subject Searches
Example: To find minerals with Si2O7 in the
chemical formula try "Si2O7".
Example: "PO4,CO3" finds all minerals with PO4 and
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Example: "PO4" "CO3" finds all minerals with PO4 and
CO3 without regard to order of occurrence.
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