TABLE III. 
Association. 
Inclusions. 
Alterations. 
Occurrence. 
Remarks. 
With augite 
saiiidine, 
nephelinCj 
hauyn, and 
leucite. 
Very poor, 
augite and 
apatite needles, 
glass inclusions. 
Primary component 
of phonolite, leuci- 
tophyr, and volcanic 
products. 
Compare Chromite. 
With olivine 
and augite. 
Most rarely 
with olivine 
and augite. 
Primary accessory 
component. In oli- 
vine rocks, serpen- 
tine and basalts. 
Picotite often as in- 
clusions in olivine. 
As above but rarely, 
more often in granu- 
lites and in metamor- 
phic (contact) rocks. 
Very similar to 
melanite; when in 
grains only chemi- 
cally distinguish- 
able. 
Melanite is, how- 
ever, almost al- 
ways crystallized, 
and so easily dis- 
tinguishable, 
a and b can only be 
distinguished 
chemically. 
The spinels maybe 
distinguished irom 
magnetite by 
transparency (in 
very thin sections.) 
and by the insolu- 
ability, 3 c and 3 d 
can only be distin- 
guished chem- 
cally. 
With plagio- 
clase augite or 
hornblende. 
Poor in inclu- 
sions. Fluid 
inclusions, 
needles of 
apatite. 
Rare in later basic 
eruptives (either pri- 
mary or as product of 
alteration of nephe- 
line). In cavities in 
phonolites, trachyte 
andesites, basalt, as 
alteration product. 
With quartz, 
orthoclase and 
biotite. 
Fluid 
inclusions. 
Very rare ; second- 
ary in quartz 
porphyry. 
With nephi- 
line, melilite, 
augite and 
olivine. 
Very poor. 
In nepheline- 
leucite— and mele- 
lite-basalts. 
Distinguished 
easily from spinel 
by color and opti- 
cal anomalies, and 
from garnet by its 
crystalline form. 
--= Leucite. See below. 
