Sterrett — New Type of Caleite from Joplin, Mo. 73 



Art. XI. — A new Type of Caleite from the Joplin Mining 

 District ; by Douglas B. Sterrett. 



During the past spring an interesting type of caleite crystals 

 has been added to those already produced by the prolific Joplin 

 region. The crystals are all twins and show a uniformity of a 

 development unusual for the species. They were obtained 

 from a small cave discovered in the Maybell Mine at North 

 Empire, Kansas. According to Mr. W. L. Bachtell, who has 

 had charge of the removal of the crystals, the cave was opened 

 at a depth of 135 feet while blasting in the chert. It was 50 

 feet long, 4 to 8 feet high and 6 to 12 feet wide. Specimens 

 were sent by Mr. Bachtell to Prof. E. S. Dana at New Haven, 

 and it is at his suggestion that this brief study of their forms and 

 development has been undertaken. These specimens, with others 

 loaned to the writer by Mr. George L. English of New York, 

 and one from the Brush collection, were used in the preparation 

 of this article. Mr. English described this new occurrence in a 

 lecture before the New York Mineral ogical club on March 15th. 

 Since his lecture was not published, it has been deemed advis- 

 able to give a brief description of the occurrence and of some 

 characteristic specimens. 



Most of the crystals are very large. Mr. English states that 

 according to the information that has come to him, prob- 

 ably less than two hundred were obtained from the cave, and 

 only some dozen or so were of a size suitable for cabinet 

 drawer specimens. One of the larger crystals, now in the 

 Yale College collection, measures 39"5 cm along the reentrant 

 angle, 19 cm in thickness and 30 cm high, according to the orien- 

 tation chosen in fig. 1. This crystal weighs 62 pounds and is 

 very well developed for one of such size. Probably the small- 

 est is the one shown in fig. 2, which is only 4'7 cm in greatest 

 length. One remarkable feature which most of these crystals 

 possess is a delicate amethystine or lilac color, much resembling 

 that of the pale-colored kunzite. The color is not uniformly 

 distributed through the crystals, but is confined chiefly to the 

 outer parts and appears to lie in a plane parallel to the crystal 

 faces, especially the e face. Owing to their form and great 

 beauty of color, they are called the "amethystine twin calcites." 



The crystals are twinned on the e face (0112), according to a 

 very common law for caleite. In representing them, drawings 

 were made with the twinning plane vertical (as in figs 1 and 2), 

 also with the lower crystal in normal position for a positive 

 form while the upper negative crystal was tilted back into 

 twin position (as in figs. 3, 1 and 5). Measurements were made 



