- published: 11 May 2015
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The mineral marcasite, sometimes called white iron pyrite, is iron sulfide (FeS2) with orthorhombic crystal structure. It is physically and crystallographically distinct from pyrite, which is iron sulfide with cubic crystal structure. Both structures do have in common that they contain the disulfide S22- ion having a short bonding distance between the sulfur atoms. The structures differ in how these dianions are arranged around the Fe2+ cations. Marcasite is lighter and more brittle than pyrite. Specimens of marcasite often crumble and break up due to the unstable crystal structure.
On fresh surfaces it is pale yellow to almost white and has a bright metallic luster. It tarnishes to a yellowish or brownish color and gives a black streak. It is a brittle material that cannot be scratched with a knife. The thin, flat, tabular crystals, when joined in groups, are called "cockscombs."
In marcasite jewellery, pyrite used as a gemstone is termed "marcasite". That is, marcasite jewellery is made from pyrite not from marcasite. In the late medieval and early modern eras the word "marcasite" meant both pyrite and marcasite (and iron sulfides in general). The narrower, modern scientific definition for marcasite as orthorhombic iron sulfide dates from 1845. The jewellery sense for the word pre-dates this 1845 scientific redefinition. Marcasite in the scientific sense is not used as a gem due to its brittleness.
If you leave me now
You'll take away the biggest part of me
Ooo oh, no, baby please don't go
And if you leave me now
You'll take away the very heart of me
Ooo oh, no, baby please don't go.
Ooo, oh, girl, I just want you to stay
A love like ours is love that's hard to find
How could we let it slip away?
We've come too far to leave it all behind
How could we end it all this way?
When tomorrow comes and we both regret
The things we said today
A love like ours is love that's hard to find
How could we let it slip away?
We've come too far to leave it all behind
How could we end it all this way?
When tomorrow comes and we both regret