68 CATALOGUE OF MINERALS ; 
CHIASTOLITE—Comp. chiefly silicate of alumina. 
In the Queensland Museum are three specimens of chiastolite 
crystals from Hann’s Northern expedition. 
Topaz—Comp. silicate of alumina in which half the oxygen of 
the silica is replaced by fluorine. 
Topaz has been found in the drift of Stanthorpe ; also in the 
Never-can-tell claim, Coolgara, Tinaroo, Herberton, with cas- 
siterite crystals, and with stream tin in Running Creek, near the 
Star River. 
XI—HYDROUS SILICATES. 
LAUMONTITE—Comp, hydrous silicate of alumina and lime. 
Mentioned by Mr. R. L. Jack as occurring in the cavities of 
the amygdaloidal trap rock of Strathmore Creek. 
CHRYSOCOLLA—Comp. hydrous silicate of copper, but generally 
with impurities. 
This mineral is not at all of common occurrence, nevertheless 
it occurs in a vein on the east side of the Townsville road, near 
Dalrymple, with native copper and malachite ; also at the Lucky 
Prop mine, near Charters Towers, and is said to have been found 
at the Mount Orange copper mine. 
PREHNITE—Comp. hydrous silicate of alumina and lime with a 
little iron. 
Found in the cavities of the amygdaloidal trap rock of Strath- 
more Creek, being frequently associated with carbonate of copper. 
GISMONDITE—Comp. hydrous silicate of alumina and lime with 
a little potash. 
A specimen in the Queensland Museum is marked Gismondite 
from Rosewood ; the matrix is a lava. 
THOMSONITE—-Comp. chiefly hydrous silicate of alumina and lime 
with some soda. 
Occurs in cavities in the amygdaloidal trap rock in Strathmore 
Creek. 
NATROLITE—Comp. chiefly hydrous silicate of alumina and soda 
with generally a little lime and iron. 
This zeolite occurs in the basalt of ‘Toowoomba and near 
Ipswich. 
