murexide

Murexide is turned, by potassa, gray in its light shades and violet in its dark ones.
Scientific American Supplement, No. 363, December 16, 1882|Various
The third group includes safflower, magenta, and murexide (light shades).
Scientific American Supplement, No. 363, December 16, 1882|Various
A little ammonia is then added, when the fine purple murexide stain will be produced.
Scientific American Supplement, No. 611, September 17, 1887|Various
The edge of the hatch split open, pouring acrid Murexide fumes into the cabin.
Gold in the Sky|Alan Edward Nourse

When an alkaline solution of murexide is precipitated by an acid, a light shining powder results, called purpuric acid.
Field's Chromatography|George Field