28 
MUSEUM BULLETIN NO. 27. 
green solution, but leaving a limited amount of flocculent residue; and that 
on heating it turns a bronze colour and becomes perceptibly magnetic. 
More recently, the mineral has been analysed by Dr. Laura Hezner. 
She refers to the stichtite as forming a rock mass composed almost en- 
tirely of a scaly mica-like mineral, recalling lepidolite, but with poorer 
cleavage and a rather oily lustre; she states that the mineral appears to 
have been derived from the serpentine, while grains of chromite in the 
latter have been converted entirely into stichtite. Dr, Hezner’s anal- 
ysis is reproduced in column (2) below. The author considers the SiO* 
and FeO, shown in the analysis, to be due to admixed serpentine and 
chromite respectively, and after removing these, the figures agree very 
closely with the formula CrjO* . 7 MgO . 2 CO 2 . 1 2HaO or 2Cr (OH)s.SMg 
(OH)*,2MgCO*.4HtO. This is taken as the formula for stichtite, and 
column (3) gives the calculated percentage composition of the mineral. 
Analyses of Stichtite. 
1 
2 
3 
SiOt 
3-87 
CO. ........... 
7-2 
11-5 
9-0 
10*45 
11*95 
Cr s O*. ... ............ ... . . ... 
20-44 
20-65 
Fe*0*. . . . . . . . 
FeO. . . . . . . . . . .... - . 
1-10 
MgO. . . . , . ...... 
36-0 
36*1 
37-12 
38-06 
H a O— 120°.\ 
0-95 
HiO+120 o / 
26-31 
29*34 
99-8 
100-24 
100-00 
1. Analysis by A. S. Wesley. 
2 Analysis by Dr. Laura Hezner. 
3. Calculated percentage composition. 
Ward examined the mineral optically. Under the microscope he 
found that it has the form of fibres and tufts, sometimes curved, radially 
disposed about nuclei of chromite. The radiating aggregates are wrapped 
round with a mosaic of small scales and fibres. He states that the min- 
eral is not perceptibly pleochroic, that the fibres have parallel extinction, 
and are optically positive (measured with respect to their elongation), 
and that the birefringence is strong. 
The physical and optical characters were later determined by 
Himmelbauer. He describes the mineral as occurring in scales with a 
good basal cleavage. Hardness If; specific gravity 2-161, Optically 
uniaxial, or occasionally feebly biaxial, negative. Refractive index of 
flakes, determined by immersion in a mixture of benzol and nitro-benzol, 
1*542; birefringence, v—e -0-026; pleochroism weak, o) > c. He fur- 
ther states that the radial arrangement of the flakes around the chromite 
grains, as seen under the microscope, indicates that the latter mineral 
