Hewett and Shannon — Orientite. 491 



Art/XXXVII. — Orientite, a new hydrous Silicate of Man- 

 ganese and Calcium from Cuha;^ by D. F. Hewett^ 

 and Earl V. Shannon.^ 



Contents. 

 Introduction. 

 Part I. 



Mode of Occurrence. 



Associated Minerals. 



Paragenesis. 



Genesis. 

 Part II. 



Crystallography: General character; habits; combinations; forms and 

 angles. 



Physical properties: color; cleavage; hardness; specific gravity. 



Optical properties. 



Composition and chemical properties : analyses; pyrognostics. 



Eelations to other minerals. 



The amorphous material. 



Introduction. 



Introduction. — In the course of the examination of some 

 manganese deposits in Oriente Province, Cuba, during 

 March and April, 1920, a crystallized silicate of manga- 

 nese and calcium was discovered by D. F. Hewett. After 

 preliminary tests, specimens were sent to E. V. Shannon, 

 who determined that the mineral was a hydrous silicate 

 of manganese and calcium and represented a new species. 

 In the following statement, the crystallographic, optical 

 and chemical studies have been made by Shannon and 

 those with reference to mode of occurrence and genesis 

 by Hewett. 



As the mineral is known to occur in two localities in 

 Oriente Province, where many manganese deposits are 

 f ound,^ and it may be widespread in the region, it is appro- 

 priate that the geographic relation be perpetuated in the 

 name orientite. 



Part I. 



Mode of Occurrence. — The province of Oriente roughly 

 coincides with a broad structural trough in the rocks, 



^ Published by permission of the Director of the IJ. S. Geological Survey 

 and the Secretary of the Smithsonian Institution. 



- Geologist, U. S. Geological Survey. 



^ Assistant Curator, Department of Geology, U. S. National Museum. 



■* Hayes, C. W., Vaughan, T. W., Spencer, A. C, Eeport on a geological 

 reconnaissance of Cuba made under direction of Gen. Leonard Wood, 1901. 



Burchard, E. F., Manganese-Ore Deposits in Cuba, Trans. Am. Inst. Min. 

 & Met. Eng., vol. 63, p. 51-104, 1920. 



