AMERICAN MUSEUM GUIDE LEAFLETS 
distinguished from calcite by the fact that they unite in curved group- 
ings and by their differences of color. The series of siderite and rhodo- 
chrosite in Case E is especially fine. Aragonite is a second form of 
calcium carbonate and one which crystallizes in an entirely different 
way from calcite. Among the suite in Case 9, attention is particularly 

ARAGONITE FROM. STEIERMARK, AUSTRIA 
“‘Flos-ferri’ in stalactitic shapes 
directed to the branching coral-like forms which distinguish the cave 
deposits of aragonite and which, with their delicate lace-work of fine 
stalactitic stems, constitute objects of great attractiveness of form. 
Cerussite, the carbonate of lead, is related to aragonite in much the 
same way that the minerals of the group containing dolomite, siderite, 
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