OS MINERALS. ■ ? y. Blackish lead grey is common lead grey mixed with a little black. Examples, silver glance and copper glance. 2. Whitish lead grey. This variety passes into tin white. Example, native arsenic. b. Bluish grey is ash grey mixed with a little blue. Ex amples, hornstone and limestone. c. Smoke grey is ash grey mixed with a little brown. Example, flint. d. Pearl grey is ash grey mixed with a little crimson red and blue, or bluish grey with a little red. It passes into lavender blue. Examples, quartz, procelain jasper, and crystallised hornstone. e. Greenish grey is ash grey mixed with a little emerald green, and has sometimes a faint trace of yellow. It passes into mountain green. Examples, clay slate and potstone, /. y ellowish grey is ash grey mixed with lemon yel low and a minute trace of brown. It passes into yellowish brown and ochre yellow. Examples, calcedony and mica. g. Jsh grey is the characteristic colour. Example, quartz. h. Steel grey. Dark ash grey in which there appears sometimes to be a little blue, and has a metallic lustre. Examples, fahl ore, and native platina. C. BLACK. It presents fewer varieties than any of the other colours* P^ing probably to the intermixture of lighter colours not >ng observable in it. The discrimination of its varieties Attended with considerable dillicultv, and can only be satisfactorily accomplished after much practice.