92 TERMINOLOGY. 



of support; 2. Those in which the individuals form one 

 the support of the other; and 3. Those in which the sup- 

 port is cylindrical, sometimes a simple line, sometimes a 

 tube. 



Among those of the first division, we find the implanted globu- 

 lar shapes. They arise, if very thin capillary crystals, or in gen- 

 eral, such as have one of their dimensions considerably surpassing 

 the others, are fixed with one of their ends to a common point of 

 support, from which they diverge in every direction. The mode of 

 the formation of such globular shapes is more apparent, if the num- 

 ber of the individuals is not so great that they touch each other on 

 all sides. The implanted globules must necessarily be incomplete, 

 because the implanted crystals of which they consist are themselves 

 incomplete, and therefore they leave no impression when detached 

 from their support. Globular shapes of this kind occur very fre- 

 quently in Stilbite, Gypsum, and Arragonite. 



If, during the formation of several globules, they come into con- 

 tact with each other, there will arise reniform and botryoidal shapes, 

 which therefore, are nothing else than several implanted globules 

 joined together. The single globules are separated from each other 

 by faces of composition. These compositions are very frequent in 

 Haematite, Chalcedony, Wavellite, Sac. In some instances, as for 

 example in Chalcedony, the individuals become so delicate as to cease 

 to be any longer observable. 



To the present class, belong also the fruticose shapes, which 

 possess some resemblance to parts of certain plants, and most of 

 those commonly called dendritic, the latter of which may penetrate 

 throughout the whole mass, or only be superficial. 



The second division contains among others, the dentiform, the 

 filiform, and the ca.pillary shapes. These arise, if one implanted 

 crystal is the support of another, this of a third and so on ; so that 

 rows of such crystals are produced, as may be seen in Native Cop* 

 per and Native Silver. 



Sometimes several rows of individuals thus composed, join within 

 one and the same plane in certain constant directions, so that the 

 individuals of the one of these series do not join with those of the 

 other, but remain separate. Thus the dendritic shapes are produ? 

 ced, as seen in Native Silver and Native Gold. 



