<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">marcasite</topic></authority><related type="other"><topic>pyrite</topic></related><related type="other"><topic>white iron</topic></related><related type="broader"><topic>mineral</topic></related><related type="broader"><topic>gemstones by specific type</topic></related> <note xml:lang="en"><![CDATA[ A mineral with the same composition as pyrite (fool's gold) but differing in crystal structure. It can be faceted like a gemstone; it was popular in the 1920s to 1930s, usually set in sterling silver. It is commonly found as nodules and concretions in sedimentary rocks. ]]></note></mads>