134 Field Columbian Museum — Geology, Vol. III. 



BARITE 

 CARTERSVILLE, GEORGIA 



FIGS. 1-3, PLATE XLVII 



A fine suite of barite crystals from the above locality was pre- 

 sented to the Museum in the fall of 1902 by Prof. S. W. McCallie, the 

 present State Geologist of Georgia. The specimens have the Museum 

 Nos. M 7172-7235. While the occurrence of barite at the Carters- 

 ville locality has been described before, its crystallographic characters 

 do not seem to have been given in detail. It seemed, therefore, desir- 

 able to make a crystallographic study of this suite. 



The manner of occurrence of the barite has been fully described 

 by Hayes* who states that it accompanies bodies of ocher occurring 

 in the Cambrian quartzite of the region, the ocher being mined ex- 

 tensively for economic purposes. Numerous passages and cavities 

 penetrating the quartzite and ocher are lined, Hayes states, in the 

 case of the smaller cavities with a crust of small quartz crystals, 

 while the larger ones frequently contain beautiful crystals of barite, 

 which according to Hayes, "were probably deposited after the con- 

 ditions favorable for the solution of silica and the deposition of ocher 

 had passed." Hayes also says, "Groups of acicular crystals of this 

 mineral several inches in length are not uncommon. It also occurs 

 in white granular veins. The barite is called 'flowers of ocher' by the 

 miners. It remains in the residual soil which covers the quartzite 

 outcrops and affords the best means of tracing the ocher deposits. 

 It is found at numerous points on the low quartzite ridge north and 

 south of the Etowah river ; and prospecting at these points has never 

 failed to reveal more or less extensive deposits of ocher." 



The crystals in possession of the Museum form, as a rule, interpen- 

 etrating groups or clusters, some of which are nearly a foot in length. 

 The individuals of the group are often largely made up of aggregates 

 having the macro-axis in common. These combine so as to produce 

 a polysynthetic individual with serrated edges. The crystals are 

 transparent to translucent except where the ocher enters into their 

 substance in quantity, in which case it renders them opaque. The 

 color of the transparent crystals is a delicate greenish-blue; but the 

 crystals that are opaque partake to a greater or less degree of the 

 yellowish-brown color of the ocher. 



* Geological Relations of the Iron Ores in the Cartersville District, Georgia, Trans. Amer. 

 Inst. Mining Engineers, 1900, Vol. XXX, p. 418. 



