<?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">touchstone</topic></authority><related type="broader"><topic>flint</topic></related><variant type="other"><topic>Lydian stone</topic></variant><variant type="other"><topic>basanite</topic></variant><variant type="other"><topic>stone, Lydian</topic></variant> <note xml:lang="en"><![CDATA[ A velvety-black variety of cryptocrystalline quartz, siliceous shale, or similar substance used by jewelers for testing the purity of precious metal, especially gold, by the streak left on the stone when rubbed with the metal. ]]></note></mads>