46 
THE CAROLINE STONY METEORITE 
mm. wide are embedded in the silicates or in interstices 
between them and correspond to the small particles of 
chromite recognized in transmitted light. The grains are 
hard, resistant to weathering, and distinguished on polished 
surfaces by their colour, greyish white with a tinge of brown ; 
they are isotropic and resistant to all standard etching agents. 
Their shape is at times suggestive of octahedral outlines. 
They are free from inclusions except in rare instances when 
they appear to enclose small particles of pyrrhotite or of a 
silicate ; narrow veins of iron-oxide occasionally extend from 
surrounding areas into a grain of chromite, sometimes dying 
out within the limits of the crystal, sometimes cutting through 
it. Pyrrhotite when in contact with chromite appears to be 
moulded on it. The edges of small particles excavated from 
the polished section and examined in transmitted light, are 
translucent and dark green merging in places into brownish. 
Normal chromite grains are brownish in transmitted light, 
and the green tint may indicate an isomorphic mixture of 
chromite with picotite or hercynite. 
The presence of chromium was confirmed by a qualitative 
“spot” test with diphenylcarbazide. Powdered meteorite 
was fused on a platinum wire in a bead of potassium carbo- 
nate and potassium chlorate ; the bead was dissolved in water, 
the solution concentrated, and then acidified with two drops 
of 1 :1 H2SO4. Two drops of a 1 per cent, alcoholic solution of 
diphenylcarbazide added to this solution gave the violet-blue 
colouration characteristic of chromium in the absence of 
mercury and molybdenum, neither of which is present in the 
meteorite. The same test applied to particles of chromite 
excavated from the section gave a similar positive result. 
Trevorite. Weathering has produced numerous narrow, 
anastomising veins of limonite in addition to isolated areas 
of limonite derived from pyrrhotite and nickel-iron. Many 
of these veins are extremely narrow, others are 0 2 mm. wide, 
and still wider areas of limonite occur at the intersection 
of veins and in other localized areas. Colloform banding in 
many veins is indicated on polished surfaces by different 
shades of grey assumed by different varieties of limonitic 
hydroxides, and in places the banding is accentuated by very 
thin lines of a whiter mineral, possibly hematite. Trevorite, 
Ni0.Fe20s, sometimes forms part of the banding (Fig. 3), 
and small massive areas within the vein; trevorite was also 
observed as a small crystal attached to a limonitic pseudo- 
morph after nickel-iron. 
Trevorite was established as a mineral species by Walker 
