of this amber varies from yellow, golden brown, red to 
black; the most common being the yellow and golden 
brown hues. Variety in appearance tended to indicate 
that several kinds of trees might have produced the am- 
ber. All but two specimens fit into two spectral patterns 
indicated as Type I (H_ 1A) and Type II (H 88), Plate 
XXIII. A third type (H 1C) gives an ill defined spec- 
trum. It was, therefore, initially assumed that these three 
patterns might indicate three different sources (Langen- 
heim, 1963). The two major types (14 samples of each), 
however, are similar to each other, except for the more 
general flattening of the bands and loss of the sharp band 
at 11.2—11.3p (895-885 cm-!) in Type II. The similarity 
is now thought to be sufficient to suggest that both Type 
I and Type II were derived from the same source and 
that the differences may be explained by additional at- 
mospheric oxidation and progressive polymerization. The 
two specimens representing Type III (H 1C, Plate 
X XIII) are black in general appearance, although small 
pieces show aruby red color in transmitted light. The 
pieces are extremely soft and friable, indicating that they 
had been partially decomposed. Type I had aspectrum 
similar to that of Hymenaea Courbaril (H 1B-IV, H 58, 
Plate XXVIII), although there are some differences. 
Langenheim and Beck (1965) explained that the broad 
band at 14.2-14.4 (705-700 cm!) due to unassigned 
skeletal vibration has disappeared in the amber. The 
11.3 (885 cm-!) band which can be assigned to =CHg 
out-of-plane deformation of terminal carbon-carbon 
bonds decreases, as would be an expected result of pro- 
gressive oxidation by atmospheric oxygen. The attend- 
ant formation of new carbon-oxygen bonds would also 
account for the slight shift of absorption maximum near 
8 (1250 em-!) which is more often at 7.6 (1295 em:!) 
in the Hymenaea resin but more often at 8. 1p (1285 cm!) 
[ 93 ] 
