820 Dr, Davy on the Geology and Mineralogy of Ceylon, 
and are very apt to decompose : the best and most perfect crys- 
tals of this mineral, that I have met with, has been at Trinco- 
malie, in quartz rock. The precious garnet occurs but in a few 
places, and I have not yet seen it of good quality ; at Trincoma- 
lie it is contained in hornblende rock. Pyrope is comparatively 
rare : I have met with a small quantity of it in decomposing gneiss 
at Matura. Cinnamon-stone, though an abundant mineral in this 
island, to which it is peculiar, is found in few places only ; indeed 
I can mention only two localities with certainty — Cotta, where it is 
found in small irregularly shaped masses in gneiss alluvion, and near 
Belligam, where it enters into the composition of a large detached 
rock, with felspar, quartz, hornblende, and graphite, which are the 
other constituent parts. The thick wood, round the spot where this 
interesting rock occurs, prevented me from examining the adjacent 
country. From what I saw, I was inclined to suppose the rock a 
part of a vein, and that it had rolled down from higher ground, 
the nearest rocks to it consisted chiefly of gneiss or felspar. I may 
here mention, that there is a doubtful kind of cinnamon stone, which 
occurs in many places, as in the gneiss at Colombo, Mount Lavinia, 
Dodrah head, &c. ; it is disseminated in very small masses, has 
the fracture and lustre of cinnamon stone, is semitransparent, and 
never crystallized : it certainly belongs to the garnet family ; I am 
disposed to consider it merely as a variety of cinnamon stone, from 
which it appears to me to differ only in being of a redder hue, and 
in this respect approaching pyrope. 
4. The zircon family is certainly more numerous in Ceylon than 
in any other part of the world. As far as my knowledge extends, it is 
confined to the districts of Matura and Saffragam : it is most abun- 
dant, I believe, in the former, as is indicated by the popular name, 
“ Matura Diamond,” which is applied to the finest varieties of zir- 
con by the dealers in gems. Besides the two well established species, 
