The blow-pipe or dry test for minerals is convenient to apply to small
bits or splinters of a stone.
The mineral is either held by a pair of platina-pointed forceps, or
powdered and placed on a metal plate or in a glass tube.
Before the blow-pipe, some minerals change color, but do not melt,
while others retain their color, or swell up, or break into small
particles, or melt into colorless or colored glasses.
The following is the scale of minerals used to test the different
degrees of fusibility:
1. Gray Antimony. Fusible in coarse splinters in
summit of candle flame without the blow-pipe.
2. Natrolite. Fusible in fine splinters in the summit
of a candle flame without the blow-pipe.
3. Almandite. Does not fuse in candle flame; fuses
easily before the blow-pipe in obtuse pieces.
4. Green Actinolite. Fusible before the blow-pipe in
coarse splinters.
5. Orthoclase. Fusible before the blow-pipe in fine
splinters.
6. Bronzite. Before the blow-pipe becomes rounded only
on the sharp edges.