Pyrite is a very common mineral that had many a hopeful gold digger go into a brief paroxysm of delight over time. Because of its golden hue it is often confused with gold, and therefore also known as 'fool's gold'. This connection is not entirely wrong, however, since pyrite sometimes is found together with gold.
Pyrite consists mainly of iron and sulfur and is exploited in the first place for the production of sulfur dioxide. It is also turned into jewelry, but since pyrite is sensitive to warmth and acid, it is not fit for daily wear. This may be the reason why it is used as mourning jewelry – as funerary objects thus, or as jewelry worn while in grief.