marble scourer (mar blskour"er)

An implement for scouring marble floors, constructed and acting on the same principle as the marble rubber, but having a handle by which the workman, in a standing position, can conveniently operate it. ca ite, march a site, marc he site; Also great pieces of chrystal, amethysts, gold in ye mine, and other mettals and marcasites. Evelyn, Diary, June 21, 1650. Half the ladies of our acquaintance carry their jewels to town, and bring nothing but paste and marc a sites back. Goldsmith, She Stoops to Conquer, iii. 2. In recent use, the orthorhombic iron pyrites, or iron disulphid, FeS2. It has a lower specific gravity than ordinary pyrite, and on an untarnished surface a somewhat paler color, in consequence of which it is often called white iron pyrites. The crystallized varieties take various imitative forms called cockscomb pyrites, spear pyrites, etc.; the ma ive kinds are often radiated, concretionary, etc. Marcasite is much more liable to alteration than ordinary pyrite, pa ing by oxidation into iron sulphate or copperas. The two kinds of iron pyrites often occur together, and the greater the proportion of marcasite the more the liability to alteration; this has been shown (Julien) to be an important element in the durability of building-stones containing pyrites.