252 
MANGANESE DEPOSITS OF INDIA : GEOLOGY. [ PaRT II : 
about ~ to I inch in diameter and are either well rounded or partly 
bounded by small unrecognizable faces. They often show a bright 
lustre and. on a fresh fracture, are seen glistening from the light-coloured 
matrix. The spandite varies in colour in the rocks of various locali- 
ties from deep orange to orange-red and blood-red, and never shows 
the yellow and lighter orange coloiirs of the spessartite of the Central 
Provinces. Under the microscope these garnets show various tints of 
pale-yellow, pale orange, and pale orange-brown. 
Manganese-pyroxenes. — The least common of these is a rose-pink py- 
roxene, probably rhodonite. This is best seen at Chintelavalsa and Taduru, 
where it forms a coarsely crystalhne rock composed of varpng proportions 
of rhodonite and the other manganese-pyroxenes, with a certain amount 
of orange-coloured garnet. It is not certain whether there are only two 
other pyroxenes besides rhodonite, or three. These other pyroxenes are 
also best seen at Chintelvalsa and Taduru, where they form a coarsely 
granular rock with rhodonite. The supposed three varieties are brown, 
green, and brownish green, in colour, and an account of them is given on 
page 137. As the first-named is often of a rich orange-brown colour, it 
may easily be mistaken macroscopically for the manganese-garnet. The 
pyroxene seen at Kodur is usually entirely changed into a pseudomorph 
of soft brownish black manganese oxide still showing the cleavage of the ^ 
pyroxene ; but, where less altered, it appears to be blackish green. 
Until the manganese-pyroxenes of the various locahties are critically ex- 
amined it will be impossible to say how many species or varieties 
there are. At Kodur some of the altered forms of p}T0xene are an inch 
and more in diameter. 
Biotite. — This is found at Ramabhadrapuram and shows the ordinary 
pleochroism, brownish straw to dull orange-bro^^Ti ; it might, from its 
mode of occurrence, be expected to be mauganiferous, but this point has 
not been determined. It also occurs at Chintelavalsa in a complex 
rock composed of spandite, rhodonite, green pyroxene, quartz, apatite, 
sphene, and graphite, and at Garbham in apatite-manganmagnetite 
spandite-rock. 
Graphite. — This is abundant in the Chintelavalsa rock noticed in the 
preceding paragraph. It occurs in scales up to | inch diameter. It 
13 also found in various rocks at Taduru (see page 11J2). 
Sphene.— The only occurrence is in the rock mentioned under ' biotite', 
in which it occurs in small crystals distinguishable only imder the 
microscope. 
