Crossword-Solution: DICHROIC 8 letters, 1 clue 🏆 scrabble score: 16

The coloring matter, of which the free base has the formula-- (C_{6}H_{4}N(CH_{3})_{2})--N==(C_{17}H_{19}NO_{4}) forms an amorphous mass with a bronze-like luster; it is sparingly soluble in water, freely so in alcohol, its alcoholic solution being strongly dichroic; its green colored solution in concentrated sulphuric acid becomes successively blue and violet on dilution with water; it dyes silk, wool, and gun cotton, but is not fast to light.

How clear and distinct are these changes may be viewed without it in substances strongly dichroic; for instance, if common mica is viewed in one direction, it is transparent as polished plate-glass, whilst at another angle, it is totally opaque.

The augite is mostly brown, often with a purplish tinge, hardly at all dichroic, but frequently showing zonal or hour-glass structure, and various types of twinning.

Now, thanks to the scientific workers, there has been devised a relatively simple and comparatively inexpensive instrument called the _dichroscope_, which enables one to tell almost at a glance whether a stone is or is not dichroic.

The hornblende is usually pale green and feebly dichroic, but, in some eclogites which are allied to garnet-amphibolites, it is of dark brown colour.