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Table 1 INAA bulk chemistry for architectural Seneca sandstone used for two Washington, DC structures expressed as weight per cent

From: Rock varnish on architectural stone: microscopy and analysis of nanoscale manganese oxide deposits on the Smithsonian Castle, Washington, DC

Oxide/El Castle1 Castle2 Castleavg DC jail1 DC jail2 DC jailavg Overallavg
SiO a2 56.26 53.36 54.81 57.76 57.40 57.58 56.20
Al2O3 22.94 25.05 24.00 23.21 23.26 23.24 23.62
CaO 0.58 0.64 0.61 0.33 0.23 0.28 0.45
MgO 0.16 0.20 0.18 0.00 0.00 0.00 0.09
Fe2O b3 6.15 6.53 6.34 4.57 4.61 4.59 5.47
K2O 2.83 2.91 2.87 3.26 3.84 3.55 3.21
Na2O 10.22 10.41 10.32 10.12 9.92 10.02 10.17
TiO 0.75 0.78 0.77 0.62 0.62 0.62 0.69
MnOc 0.04 0.04 0.04 0.06 0.05 0.06 0.05
Fe 4.30 4.57 4.43 3.20 3.22 3.21 3.83
Mn 0.03 0.03 0.03 0.05 0.04 0.05 0.04
Fe/Mn 138.76 147.43 143.14 68.79 83.27 69.09 98.80
  1. aComputed by difference; 100-Σall measured oxides (note: H and P not measured)
  2. bTotal iron expressed as Fe3+
  3. cTotal manganese expressed as Mn2+