SiO₂ 58.11 78.31 5.19
Al₃O₂ 15.40 4.76 .81
Fe₂O₃ 4.02 1.08 .54
FeO 2.45 .30
MnO 2.44 1.16 7.89
CaO 3.10 5.50 42.57
Na₃O 1.30 .45 .05
K₂O 3.24 1.32 .33
H₂O+ 3.66 1.32 .56
H₂O- 1.33 .31 .21
CO₂ 2.63 5.04 41.54
TiO₃ .65 .25 .06
P₃O₅ .17 .08 .04
SO₃ .65 .07 .05
Organic carbon .80 — —
(100.) (100.) approx. (100.)
Many persons upon learning that average shale, and even “clay dirt,” may
contain 15% alumina, Al₂O₃ (equivalent to almost 8% metallic aluminum),
become thoughtlessly and erroneously enthusiastic about aluminum ore
possibilities on their farms or properties. The aluminum is there all
right, but it is so securely combined with silica and other elements
that the cost of extraction is now greater than the price of aluminum
obtained from less abundant ores. Until chemists find a method of
extraction of the metal from ordinary clay or shale that can be carried
out at considerably less expense than is now possible, the vast
quantities of clay and shale on the earth’s surface must be considered a
distant reserve of a prohibitively high cost aluminum.
Missouri possesses a little bauxitic clay in the southeastern part of
the state but unfortunately does not contain deposits of high grade
bauxite, the chief ore of aluminum, and so does not contribute to the
aluminum production of the United States (see the discussion under
DIASPORE CLAY). Arkansas is a leading producer of bauxite, but the
geological conditions present in that bauxite locality are so different
from Missouri geology that little hope is held for finding bauxite in
Missouri, except possibly in the extreme southeastern part.