Average EPMA chemical analyses and calculated mineral formulas.

Average EPMA chemical analyses and calculated mineral formulas of selected unexpanded vermiculite ores.

Detailed Description

Table 2.   Average EPMA chemical analyses and calculated mineral formulas of selected unexpanded vermiculite ores.

Notes: Compositions of bulk samples not individual minerals.  n = number of microprobe spot analyses collected on multiple mica flakes used to calculate the averaged composition of each sample.   ---- = not enough cation Al and/or Mg to assign to this site.  Cation sites were filled according to Deer et al. (1966).  Spectral results are consistent with some Mg in the Louisa sample occupying interlayer sites.

a Essential water = total water (released from 25 to 950 °C) minus absorbed water (released at ≤70 °C).

b Proportion of Fe3+ and Fe2+ calculated from Mössbauer analysis.

c Spectral absorptions near 3625 cm-1 indicate the presence of octahedral layer vacancies in ALB1VA00 and Zonolite® 4, with trace levels in the other two selected samples, indicating that more Mg resides in the interlayer site than is shown in the table above.  

d Interlayer water molecules per formula unit = essential water minus 4(OH) water equivalent.

Details

Image Dimensions: 952 x 1136

Date Taken:

Location Taken: US