NOTES AND QUERIES. 



167 



museum at Rio Janeiro a fragment of pure quartz two or three inches in 

 diameter contains two cavities, which are both filled with small fragments of 

 quartz and oxide of iron, which are firmly cemented by a clayey cement ; in 

 one of the cavities a diamond is seen in the middle of the conglomerate. We 

 have also been assured that near Diamantina diamonds have been found among 

 the stones composing the little cylindrical tubes which certain wormlike insects 

 of the mountains on the coast construct to protect themselves. 



Another remarkable fact which has not been previously noticed, is the dis- 

 covery in the cascalho of small fragments of quartz having a form like an 

 anvil. They have clearly been polished, and have therefore been constructed 

 by the Indians, who used them as earrings. At Grao Mayor, M. Darnel 

 Casimer Pinto-Coelho gave us one of these ; the cascalho in which it was 

 found had never been worked or disturbed in any way, and formed the bed of 

 a water-course nearly dried up ; it was even covered over by more than six 

 yards of vegetable mould, on which beautiful palm trees were growing. The 

 polished quartz ornaments are accompanied by other cut objects, principally 

 arrow-heads ; bones also occur, of the nature of wliich we have not been able 

 to pronounce. 



These traces of human industry met with in the virgin cascalho prove it to 

 be of comparatively recent origin, consequently also the red race must be very 

 ancient. It is to be hoped that the researches of Dr. Lund on the bones 

 found in the neighbouring caverns will throw some light upon this important 

 question. 



We will point out two or three more names in common use. The cascalho 

 of the old water-courses is called " Gupiara;" that accumulated at the heads of 

 the rivers " Tabuleira ;" lastly " Corrido," is the name given to the half- 

 rounded pebbles found in the present rivers. 



Itacolumite and metamorphic schist are, beyond doubt, the beds in which 

 the diamond and all other precious stones with which it is found originate. 

 Nevertheless, these gems are not necessarily met with, any more than the green 

 tourmaline of Campo Longa and the realgar of Brimenthal are seen in all the 

 dolomites of the Alps. The diamond is found in the mountains of itacolumite 

 of Grao Mayor, also in the numerous streams which flow therefrom ; it exists 

 equally in many other mountains of itacolumite, but it is too rare to be searched 

 for with advantage. Thus, in the Serra do Cipo, in the basin of the San Fran- 

 cisco, we have seen four diamonds which have been found in a small stream 

 near the upper part of this Serra. On the other hand, the mountains of itaco- 

 lumite do not necessarily contain diamonds, and in that of Itacolumi, which 

 gives its name to the rock, diamonds are not found. To the present time the 

 metamorphic and decomposed schist of San Joao or of Quinda is the only one 

 in which the diamond has been observed ; but the large tract of the gurgulho 

 do campo shows that this schist is very extensively spread, and it ought to con- 

 tain diamonds in various localities. 



The following are some remarks that we have made on the distribution and 

 associations of the minerals which accompany the diamond. 



The anatase is sometimes so pure and transparent that one is tempted to 

 mistake it for the diamond. It is, besides, associated with the sub-oxide of 

 iron, and with rutile as well as brookite. 



The euclase is always found with the topaz, and in many places to the south 

 of Ouro Preto it is in a kind of whitish clay, which seems a product of decom- 

 position. There is also specular iron-ore and rutile, like that of Saint Gothard; 

 beautiful black tourmalines, hyaline and smoky quartz. These minerals are 

 found, too, in the barro of San Joao, so that the latter appears identical with 

 the whitish clay met with in the working of the topaz. The euclase is much 

 rarer than the topaz, and as they no longer search for the latter for jewellery, 



