672 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



from the included gangue and the water being adsorbed. The remain- 

 ing constituents yield ratios as follows: 



Ratios of ludwigite from Korea. 



Fe 2 3 0. 2034] 



ALO, 022 7 } - 2261 O- 93 * 1 



BjO, 2400 .2400 .99X1 



Mg 3 - 8566 .8566 1.04X3.4 



Fe 14481 



MnO 005l| - 1499 L04 >< - 6 



These ratios place the Korean ludwigite as a member of the ferro- 

 ludwigite-magnesioludwigite series having three parts ferroludwigite 

 to 2 parts of magnesioludwigite. 



PREVIOUSLY DESCRIBED LUDWIGITES. 



LUDWIGITE (FERROLUDWIGITE) Hungary. 



The original ludwigite described by Tschermak 6 was from Mora- 

 wicza in the Banat, Hungary. Here it occurs embedded in a crystal- 

 line limestone with irregularly distributed masses of magnetite. The 

 magnetite occurs intimately intermixed with the ludwigite. The 

 material is fibrous and blackish-green to black in color. The formula 

 derived by Tschermak from the analysis is 3MgO.B 2 3 FeO.Fe,0 3 . 

 Whitfield later analyzed material from this locality and, considering 

 the water essential, arrived at the formula 3RO.R 2 3 with R = Mg,- 

 Fe,H, and R 2 = B and Fe. 7 Schaller 8 later confirmed the results 

 and formula of Tschermak. 



PINAKIOLITE, SWEDEN. 



Pinakiolite as described by Flink 9 occurs at Langban, Wermland, 

 Sweden, in bands in granular dolomite with hausmannite, etc. The 

 formula deduced from the analysis is analogous to that of ludwigite, 

 3MgO.B 2 3 .MnO.Mn 2 3 . 



LUDWIGITE, MONTANA. 



Ludwigite was found by Calkins 10 to occur abundantly with 

 magnetite and forsterite in a contact-metamorphic deposit in lime- 

 stone at the Redemption iron mine in the Philipsburg district in 

 Montana. This material has been analyzed by Schaller u who 

 found it to contain more magnesia and less ferrous iron than the 

 original Hungarian ludwigite. He assigned to the Montana material 

 the formula 3MgO.B 2 3 .(Mg,Fe)O.Fe,0 3 and predicted the existence 



« Tschermak, G., Min. Mitth., vol. 59, 1874. 

 ■> Whitfield, Amer. Journ. Sci., vol. 34, p. 284, 1887. 

 s Schaller, W. T., U. S. Geol. Survey, Bull. 490, p. 30, 1911. 

 » Flink, G., Zs. Kryst., vol. 18, p. 361, 1890. 



io Calkins, F. C, Geology and Ore Deposits of the Philipsburg quadrangle, Montana. U. S. Geol. Sur- 

 vey, Prof. Paper 78, p. 162, 1913. 

 u Schaller, W. T., U. S. Geol. Survey Bull. 490, p 28. 



