ORDER iv. HEMI-PRISMATIC HABKOXEMK-MAL. 177 



in almost every variety, and even in those masses 

 which consist of columnar particles of composition. 

 It then seems as if both the faces belonging to a 

 horizontal prism were present, forming a dihedral 

 termination of each individual, of 123 37', while 

 in fact there exists only one of them. Fascicular 

 aggregations of delicate crystals. Tuberose, globu- 

 lar, reniform, botryoidal, and stalactitic shapes : 

 surface drusy, rough, sometimes smooth ; compo- 

 sition columnar, generally very thin, often impalp- 

 able. Very thin columnar composition produces 

 a satiny lustre ; impalpable composition is the cause 

 of conchoidal fracture. Massive : composition as 

 above. The composition is often repeated ; granu- 

 larly compound masses consist of columnar ones ra- 

 diating from a centre ; curved lamellar ones are 

 likewise composed of thin columnar individuals. 

 The surface of the second composition is often 

 rough, and particularly in curved lamellar compo- 

 sitions, covered with a white coating. 



OBSERVATION'S. 



1. The species of Malachite has been divided into fibrous 

 and compact Malachite. If the columnar particles of com- 

 position decrease in size, the fibrous Malachite is gradually 

 converted into compact Malachite, which therefore is al- 

 ways a compound mineral. These two kinds pass insen- 

 sibly into each other, and it is often difficult to tell, to 

 which of them a specimen occurring in nature should be 

 referred. 



2. Two analyses of hemi-prismatic Habroneme-malachite, 

 one by KLAPBOTH, and another by VAT T QUF.I.IV, have 

 yielded, 



VOL. II. M 



