TAB. CCI. 
ZINCUM oxygenatum. 
Oxide of Zinc, or Calamine. 
Class 3. Metals. Order 1. Homogeneous. 
Gen. 6. Zincum. Spee. 1, Oxygenatum, 
- Div. 2. Imitative. 
Oxinz of Zinc, tal. 156, was crystallized in a shape pe- 
culiar to itself. _In the present instance it occurs in the 
form of another substance, viz. Carbonate of Lime: see 
tab. 34. It is nota little remarkable that this oxide should 
thus take the place of another substance, and assume its 
form, so as to become what are termed secondary crystals *. 
They are so frequent in Oxide of Zinc as often to prove 
a very convenient help towards discriminating that sub- 
stance, otherwise not easily characterized, from the earthy 
appearance it commonly assumes. It is found in Flint- 
shire t, Derbyshire, and at Mendip in Somersetshire, as 
well as in several other parts of the United Kingdoms, in 
* When any mineral takes the place of a crystal, either by decomposing 
it or taking the cast of the mould first formed by another, it is called se- 
condary, as it is so to those formed originally by the first substance. Cala- 
mine sometimes replaces Cubic fluor, &c. 
+ Whence I have received good specimens from D. Pennant, Esq., son of 
the well-known Pennant, author of British Zoology, and the Rev. H. Davies 
of Beaumaris. 
VOL. III. re, B 
