230 
FLORIDA GEOLOGICAL SURVEY—I5TH ANNUAL REPORT 
A sample of the washed clay from the Florida China-Clay Corpora¬ 
tion’s plant, near Okahumpka, had the following physical properties: 
Physical Properties of the Florida China Clay Corporation’s Sedimentary Kaolin 
(Lab. No. 0 - 83 ). 
Plasticity, judged by feel... 
Water of plasticity. 
Pore water. 
Shrinkage water . 
Linear air shrinkage. 
Volume air shrinkage. 
Modulus of rupture, average 
Slaking test. 
Steel hard at cone 1. 
Excellent. 
34.65% 
0.59% 
34.56% 
9.5 % 
25.8 % 
201.0 pounds per square inch. 
3 minutes. 
Fire tests: 
Temperature. Linear Shr. 
Per Cent. 
Absorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
950°C. 
4.5 
34.16 
42.20 
White. 
1050 
5.5 
27.08 
45.75 
White. 
1150 
6.5 
16.12 
32.50 
White. 
1190 
12.5 
6.78 
16.10 
White. 
1230 
13.5 
4.94 
12.30 
White. 
1310 
15.5 
4.86 
12.60 
White. 
1370 
16.0 
1.60 
6.65 
White. 
1430 
17.5 
1.37 
4.38 
Light gray. 
A sample 
of the washed clay from one of the 
mines near 
humpka was tested in the laboratory of the Bureau of Mines 1 at 
Columbus, Ohio. It had the following physical properties: 
General Physical Tests of IVashed Clay from Okahumpka. 
Workability . Very plastic; molds well. 
Water of plasticity. 49.78% 
Volume air shrinkage. 32.15% 
Linear air shrinkage, calculated.... 12.20% 
Modulus of rupture, average. 181.00 pounds per square inch. 
Deformation temperature, cone 31 plus. 
Steel hard at cone 3. 
Develops small cracks in firing. 
Fire tests: 
Temperature. 
Linear Shr. 
Per Cent. 
Absorption. 
Per Cent. 
Porosity. 
Per Cent. 
Color. 
190°C. 
12.1 
32.10 
28.30 
White. 
1250 
12.5 
38.11 
27.05 
Faint cream white. 
1310 
14.4 
37.33 
23.41 
Faint cream white. 
1370 
18.7 
46.30 
7.40 
Cream. 
1410 
20.3 
49.40 
2.20 
Buff. 
2 High Grade Clays of the Eastern United States, U. S. Geol. Survey Bull. No. 
708, p. 291, 1922. 
