THE PROPERTIES ‘OF BUILDING STONES, ETC. 161 
Color. 
brown, red, yellow, buff, blue, black, and green.* Ordinarily 
The predominant colors of stone are white, gray, 
the color of a rock is not simple but composite, being a resultant 
of the different colors of the constituent minerals. 
The sedimentary rocks on account of the simplicity of their 
mineral composition approach more nearly to what is known as 
a simple color than do the igneous. The shades of brown, buff, 
yellow, red, gray, or blue imparted by a sedimentary rock are 
mainly attributable to the presence of the oxide, carbonate, or 
sulphide of iron, bitumen, and carbonaceous matter in the form 
of graphite. The white and gray colors of marble, limestone, 
and dolomite may be attributed to the calcite or dolomite of 
which the rock may be composed. 
pp. 186-224, 1886; The Collection of Building and Ornamental Stones in the United 
States National Museum, by GEORGE P. MERRILL, Smithsonian Report, Part I, pp. 
277-520 1886; Igneous Rocks, by J. F. WILLIAMS, Annual Report of the Arkansas Geo- 
logical Survey, Vol. II, 1890; Building Stone in the State of New York, by JoHN C. 
Smock, Bulletin of the New York Museum of Natural History, Vol. III, No. 10, 1890; 
Marbles and Other Limestones, by T. C. HopKins, Report of the Arkansas Geological 
Survey, Vol. IV, 1890; Stones for Building and Decoration, by GEORGE P. MERRILL, 
John Wiley and Sons, 1891 and 1898; The Onyx Marbles, by GEORGE P. MERRILL, 
Report of the United States National Museum, pp. 539-585, 1893; Marbles of 
Georgia, by S. W. McCALLtE, Bulletin No. 1 of the Geological Survey of Georgia, 1894; 
Notes upon Testing Building Stones, by T. LyNNwoop GarRIsON, Trans. Am. Soc. of 
Civil Engineers, Vol. XXXII, pp. 87-98, 1894; The Relative Effect of Frost and the 
Sulphate of Soda Efflorescence Tests on Building Stones, by LEA McI. LuqQuEr, 
Trans. Am. Soc. of Civil Engineers, Vol. XXXIII, pp. 235-256, 1895; Report on 
Tests of Metals, etc., at Watertown Arsenal; Reports of the United States War 
Department, pp. 322, 323, 1895; also 1890 and 1894; The Building Materials of 
Pennsylvania; I, Brownstones, by T. C. HopPKINs, Appendix to the Annual Report of 
Pennsylvania State College for 1896; The Bedford Oolitic Limestones of Indiana, by 
T. C. Hopkins and C. E. SIEBENTHAL, Twenty-first Annual Report of the Depart- 
ment of Geology and Natural Resources of Indiana, pp. 290-427, 1896; Properties 
and Tests of Building Stones, by H. F. Bain, Eighth Annual Report of the Iowa 
Geological Survey, 1898; The Building and Decorative Stones of Maryland, by 
GrEorGE P. MERRILL and EpwARD B. MATHEWS, Report of the Maryland Geological 
Survey, Vol. II, pp. 47-237, 1898; The Building and Ornamental Stones of Wiscon- 
sin, by E. R. BUCKLEY, Wisconsin Geological and Natural History Survey, Bulletin 
No. IV, 1898. Reference should also be made to the Engineering, Mining, Archi- 
tectural, Building, Stone, and similar technical journals in which this subject is dis- 
cussed in current articles. 
«Speaking from the purely scientific standpoint all of these are not colors,. 
although they are referred to as such in this paper. 
