Chap. VIII. ] 
MANGANAPATITE. 
205 
of the Koderma specimens the mineral from this locahty must contain 
a considerable amount of Ta20g. 
The Reverend Mr. Muzzy reports the find in the Madura district 
of a mineral resembling ferro-tantalite, this being an old name for 
tantalite.i In Nelson's 'Madura Manual ' , p. 16, (1868), the ferro- 
tantalite is stated to occur near Palani, doubtless the same place as Palni, 
about 69 miles N.-W. of Madura, in porphyritic granite, this informa- 
tion being based on the notes and specimens of Muzzy. 
Manganapatite, 
Apatite is a mineral belonging to the hexagonal system and having a 
composition corresponding to one of the two formulae 3Ca3P208. 
CaCl2 and 3Ca3P208.CaF2, according as it contains chlorine or 
fluorine, the two varieties being known by the names chlor-apatite and 
fluor-apatite, respectively. Sometimes a portion of the calcium is re- 
placed by manganese and the mineral is then known as manganapatite. 
The analyses given in Dana show TSd to 10'59% of MnO in the exam- 
ples grouped as manganapatite. These manganapatites are all fluor- 
apatites. In colour they tend to be dark green or bluish green. One 
example, namely that from Branchville, Connecticut, containing 10'59% 
of MnO, has a higher specific gravity than is usual for apatite, namely 
3'39, the ordinary value being 3'17 — 3'23. This is doubtless due to the 
high percentage of manganese protoxide, and probably a careful investi- 
gation of the specific gravities of manganapatites would point to an 
increase of specific gravity with increasing percentage of MnO. 
On page 1063 reference wiU be found to a veinlet of apatite in spandite- 
rock at the Kodur mine, Vizagapatam district. This apatite, of which I 
have several specimens, is of a lavender colour, breaks with a con- 
choidal fracture, and has then a glassy appearance. Chemical examina- 
tion shows that the mineral is fluor-apatite, small pieces of which give a 
distinct reaction for manganese. As the mineral is very much cracked 
and these cracks usually contain thin black films of manganese oxide, 
some difficulty was experienced in picking out pure pieces for this test. 
The mineral is cavernous and then sometimes shows signs of the faces 
of the hexagonal prism. In these cavities the apatite is always coated 
with a thin skin of a white enamel-like substance having a nacreous 
lustre. A small piece of the apatite was found to have a specific gravitv 
of 3'22. Under the microscope the mineral often shows numerous 
1 E. Balfour, Catal. Govt. Cent. Museum, Madras ; ' Madura, its rocks and minerals ', 
p. iv, (1855). 
