52 UNIVERSITY OF MISSOURI STUDIES 



The presence of the ammonium sulfate is unique. 



A glassy variety of barite was found in a cavity lined with 

 crested barite near Richwoods. The barite occurred as small 

 botryoidal aggregates, continuous with the edges of the crests. It 

 is perfectly transparent and closely resembles hyalite. The small 

 globules break with a conchoidal fracture. A cave at Morrill- 

 ton, Franklin County, Missouri, is said to have furnished many 

 very beautiful specimens of blue barite crystals. 



Barite has a hardness ranging from about 2.5 to 3.5 or 4, and 

 a specific gravity of 4.5. The luster ranges from vitreous to 

 resinous or pearly. Much of the "rosin-tiff" is a variety with a 

 resinous luster. This barite has no value, as the reddish color 

 which it has cannot be removed in the bleaching process. This 

 color is due to the iron oxides which impregnate the barite. The 

 barite, as a rule, is white, though some of the crystals are color- 

 less. Due to the iron oxides in the clays, the barite in them is 

 always more or less stained. The colors range thru many shades 

 of yellow and brown to white. Opaque varieties are the best for 

 most of the uses of barite. 



OCCURRENCE OF THE BARITE 



There are four common modes of occurrence of the barite, 

 but all are not of equal economic value. In discussing them, 

 their genetic relationship rather than their economic importance 

 will control the order in which they will be taken up. The four 

 types are: (a) veins; (b) disseminated deposits; (c) cave de- 

 posits; (d) residual deposits. The last is the most important 

 economically. 



Veins 



The vein deposits are very slightly developed and poorly 

 known. The development work that has been done has not been 

 carried far enough to determine the extent of the barite, except 

 where some other economic mineral has been associated with the 

 barite to act as an incentive for further exploratory work. 

 Usually this mineral was sphalerite, more rarely galena, or the 

 two together. Any barite so produced is considered as a by-pro- 

 duct. In many cases it is not even sold unless the price is high 



