• Webster's Revised Unabridged Dictionary
    • n Marcasite (Min) A sulphide of iron resembling pyrite or common iron pyrites in composition, but differing in form; white iron pyrites.
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Century Dictionary and Cyclopedia
    • n marcasite As used by the early mineralogists, the crystallized forms of iron pyrites, including more particularly the isometric species now called pyrite. This mineral was frequently used for personal decoration in the eighteenth century. It takes a good polish, and is cut in facets like rose diamonds. It was made into pins, watch-cases, shoe-and knee-buckles, and other ornaments.
    • n marcasite 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 massive kinds are often radiated, concretionary, etc. Marcasite is much more liable to alteration than ordinary pyrite, passing 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.
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Chambers's Twentieth Century Dictionary
    • n Marcasite mär′ka-sīt an iron ore, a variety of pyrites (q.v.).
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Webster's Revised Unabridged Dictionary
F. marcassite,; cf. It. marcassita, Sp. marquesita, Pg. marquezita,; all fr. Ar. marqashītha,
Chambers's Twentieth Century Dictionary
Fr.; prob. of Ar. origin.


In literature:

As neat a shape as you would see in a day's journey, with the prettiest color, and eyes as bright as those marcasite buttons!
"Audrey" by Mary Johnston
Marcasite and Pearl Hair Sprigs, Garnet & Pearl Hair Sprigs.
"Diary of Anna Green Winslow" by Anna Green Winslow
They were of gold marcasite, and 200 tons of this substance was soon collected.
"Celebrated Travels and Travellers" by Jules Verne
Nodules of pyrites and of marcasite are common in many clays, sandstones and marls.
"Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 7" by Various

In news:

In our area, many of the quarries produce coarse aggregate with small percentages of pyrite or marcasite.