316 DESCRIPTIONS OF MINERALS. 
Approaches in composition the chlorites, and may belong 
to that group. 
Gillingite from Sweden, including Thraulite from Bavaria, Hpichlo- 
rite, and Lillite, are other hydrous silicates containing iron. 
Likmannite, foliated, chlorite-like, occurs in the rifts of magnetite, 
in Sweden ; it is a hydrous iron silicate, but the iron is mostly in the 
protoxide state. 
Neotocite (Stratopeite) and Wittingite are results of the alteration of 
rhodonite, and contain manganese. (tiibelite also contains manganese 
oxide. 
Strigovite from Striegau, Siberia, and Jollyte from Bodenmais in 
Bavaria, are hydrous silicates of aluminum and iron, with little mag- 
nesium. 
CHLORITE GROUP. 
The chlorite group includes the hydrous Swdsilicates of 
the Margarophyllite Section and also some related species 
that are Unisilicates. ‘The proportion of silica is small, the 
percentage afforded by analyses being under 388, and mostly 
under 30. The minerals when well crystallized are foliated 
like the micas, and have the plane angle of the base of the 
crystals 120°, but the folia are inelastic and in some species 
brittle. They also occur in fibrous and in fine granular and 
compact forms, and the latter are usually most common. 
Green, varying from light to blackish green, is the prevail- 
ing color, yet gray, yellowish, reddish, and even white and 
black also occur; and the colored transparent or translu- 
cent are dichroic. The green color is owing to the presence 
of iron, and fails only in species containing little or none 
of it. All of the species yield water in a closed tube. 
The quantivalent (or combining-power) ratio for R+8 and 
Si is, in the 
Pyrosclerite subdivision.......... aici 
Chlorite subdivision...... Pec lie ed lees 
Chloritoid subdivision............ esd tondeeees 
The chlorite subdivision includes Penninite, Ripidolite 
and Prochlorite, together with some related dark-green to 
blackish-green species. Some species of this subdivision 
characterize extensive rock formations, making chlorite 

