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e 
NEW ZEALAND NATURE-STUDY BOOK 
TRANSPARENT, when objects can be clearly seen 
through it—e.g., clear Quartz, Calspar, thin flakes 
of Mica. : 
Properties depending on molecular arrangement : 
Srotitiry.—Minerals are said to be sectile when they 
can be easily cut with the knife—e:g., Graphite, 
Selenite. 
MALLEABILITY.— Malleable substances are those which 
can be flattened out under the hammer—e.g., Lead, 
Iron, &e. 
Ductitity.—A. ductile substance is one that can be 
drawn out into wires. 
Note.—The properties of malleability and ductibility 
belong to metals only. 
ELASTICITy.—A_ substance is said to be elastic when 
on the bending force being withdrawn it springs 
back to its former position. 
FLEXIBILITY, or the property of being bent. 
BRITTLENESS.—A_ substance is said to be brittle when 
it tends to crumble or fly to powder on being 
tapped. 
FRACTURE.—-The appearance presented by the freshly 
broken surface is known as the fracture. It may 
be curved and in other ways shell-like; flat 
and even; or rough and uneven. 
Characters depending on taste :—i.¢, taste may be— 
Saline. Sweet. Bitter. Sour, ete., ete. 
Characters depending on odour. 
HARDNESS.—This charactistic varies greatly and forms 
one of the most important tests in determining 
minerals. Thus Quartz and Calcite which are some- 
times very much alike may at once be distinguished by 
the simple expedient of testing the specimens with an 
ordinary knife-blade. A portion of the Calcite can 
