TIN DEPOSITS OF THE MALAY PENINSULA 1 45 



are very rich in cassiterite, containing from 40 to 60 per cent., 

 but this is very rare. 



Mifierals associated with the tin ore in the Kinta district. — With 

 the tin in the alluvium are associated much tourmaline, horn- 

 blende, wolframite, and magnetite, while in smaller quantities 

 are found white mica, topaz, scheelite, and sapphire, and it is said 

 that in parts of the peninsula small quantities of thorium and 

 cerium minerals have been found. Some beautiful transparent 

 topaz crystals have been found near Tapa, south of Campar. 

 Gold also has been found in small quantities in the tin alluvium. 



It is probable that all these minerals once existed in situ in 

 the rock in more or less close association with the tin. Certain 

 other minerals, such as iron pyrites, chalcopyrite, bornite, and 

 arsenical pyrites, which occur with the tin in the rock, are rarely 

 seen in the alluvium, as they have decomposed and mostly dis- 

 appeared during the erosion of the rock, though rusty masses of 

 these sulphides, partly decomposed, and associated with quartz, 

 often occur in alluvium which has not been transported far from 

 its source. 



Occurrence of tin ore iti the rocks of the Kifita district. — Though 

 the tin mined on the peninsula comes practically all from the allu- 

 vium, yet cassiterite also occurs in various places in situ in the rocks 

 of the region. It is most often found in granite, but also occurs 

 in the limestone and sandstone. It has been worked in a few 

 localities, notably in the granite at Sorakai in Perak, and at the 

 Rin mine in the Jelibu district in Selangor, while at Chongkat 

 Pari in Perak, it has been worked in limestone. None of these 

 efforts, however, have as yet been more than partially successful, 

 and most of them have eventually failed, as the ore is in too 

 scattered a condition to pay to work. Hence, though tin is 

 frequently found in the rocks as well as in the alluvium, mining 

 is mostly confined to the latter. It seems not impossible, how- 

 ever, that deposits may yet be found in the rock that can be 

 profitably worked. 



Where the tin is seen in situ in the granite, it occurs in 

 pockets, small veins, or a combination of stringers intersecting 

 each other in various directions in the form of a network, while 



