marcasite
white iron pyrite

This problem appears to be significantly worse if any marcasite is also present.

It was a delicate, old-fashioned, marcasite one that had cost too much and didn't keep time very well.

Marcasite can be formed as both a primary or a secondary mineral.

Pyrite is similar to marcasite, but more stable and less brittle.

Marcasite in the scientific sense is not used as a gem due to its brittleness.

The connectivity of the atoms is more similar to that in marcasite than pyrite.

"I like your pin," President Clinton said, pointing to my marcasite brooch.

Specimens of marcasite often crumble and break up due to the unstable crystal structure.

Marcasite reacts more readily than pyrite under conditions of high humidity.

Marcasite jewellery has been made since the time of the Ancient Greeks.

This disintegration of marcasite in mineral collections is known as "pyrite decay".

Most of the sulfides are pyrite or marcasite contained in the raw materials.

Among his more unusual items is a pin of marcasite, sterling and enamel, showing the 1939 theme buildings.

Pyrite is used to make marcasite jewelry.

Marcasite is lighter and more brittle than pyrite.

Brazilian coal is characterized by high sulphide contents, pyrite and marcasite.

Sterling silver necklace features a semi-precious stone pendant with marcasite accents.

They had belonged to her mother - silver and marcasite wings with a small pendant pearl; not valuable, but of personal importance.

Sulfide minerals such as galena, sphalerite, marcasite and pyrite thus form.

Pyrrhotite is often accompanied by pyrite, marcasite and magnetite.

He bought marcasite stones, mainly in Czechoslovakia, that were used by Paris milliners at the time.

Julia checked her antique marcasite watch.

Pyrite and marcasite, which are diamagnetic minerals, have the formula FeS.

The second order minerals are marcasite, hematite, malachite, azurite, native gold and silver.

The narrower, modern scientific definition for marcasite as orthorhombic iron sulfide dates from 1845.

The mineral marcasite, sometimes called white iron pyrite, is iron sulfide (FeS) with orthorhombic crystal structure.