666 As Sc TEESE 
Superhard, fine-grained, argillaceous, and seemingly slightly cal- 
careous, subvitreous luster. 
Texture granular. Constituents dolomite 90 per cent; quartz 
5 per cent; small amounts of magnetite, glauconite, ilmenite as 
accessories, and limonite as alteration product. Cement dolomite 
and limonite. 
Dolomite in rhombs, inclusions of limonite; averages 0.07 mm. 
Quartz rarely over 0.02 mm., very angular. Glauconite altering 
to limonite, latter also between dolomite crystals. 
Classed: glauconitic superfine-grained dolomite. 
