and Mineralogy. 51 9 
metallic lustre, the latter iiiclucles every reniaiiiing variety, even 
the incomplete metallic lustre. In adamantine lustre, we distin- 
guish the metal-Vike and the common. The first is found in 
wolfram, in the dark varieties of red-silver and cinnabar, in dif- 
ferent varieties of blende and white lead-spar ; the second in 
diamond, in the bright-coloured varieties of red silver and cin- 
nabar, and others. The mother-of-pearl lustre may be distin- 
guished into common and metal-like mother-of-pearl lustre. The 
first is found in foliated zeolite, in kyanite ; the second in yel- 
low orpiment, in schillerspar, and others. The resinous and vi- 
treous lustres require no farther subdivision. In adours, we 
have separated the metallic from the non-metallic : The first 
only is used in the present system of characters. As to 
those other designations, which have been altered, or more 
strictly limited to serve the purposes of this system, we ima- 
gine it will be shorter to explain them afterwards, than to ex- 
hibit them here under a general aspect. 
II. Of Individuals in the Mineral Kingdom ; of Simple and 
Compound Minerals ; of Homogeneity^ Species, Genus, 
1. Erroneous ideas of Individuality . — The idea of individua- 
lity in the mineral kingdom is one of those concerning which 
the greatest number of errors have been entertained. Karsten, 
Steffens, Link, and Bernhardi, have all submitted to the pu- 
blic incorrect notions upon this point. It is a subject of im- 
portance for the right understanding of some others (7. 8.) 
which are founded on it ; and hence, in treating of natural his- 
tory, to pass it over in silence would be unsatisfactory. 
% Correct idea. Eocplanaiion hy examples . — Generally 
speaking, the name of Individual, in natural history, is given 
to any thing or substance which, by itself, is capable of becom- 
ing an object of contemplation in this department of science, 
and which, therefore, appears as a whole, or must be represent- 
ed as a whole- In the mineral kindgom, any crystal of calca- 
reous-spar, for example, is an individual ; any grain of diamond 
or garnet, for example, is an individual ; but a fragment, for 
instance, of granular limestone, is not sq. The former are 
wholes,' and by division cease to be wholes ; the latter is not a 
' Y 2 
