<?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">concretionary stone</topic></authority><related type="narrower"><topic>septarium</topic></related><related type="broader"><topic>sedimentary rock by form</topic></related><variant type="other"><topic>concretionary stones</topic></variant><variant type="other"><topic>stone, concretionary</topic></variant> <note xml:lang="en"><![CDATA[ Rock characterized by, consisting of, or producing concretions; concretions are hard, compact aggregates of mineral matter, subspherical or irregular in shape, formed by precipitation from water solution around a nucleus, such as a shell or bone, in a sedimentary or pyroclastic rock. Concretions are generally different from the rock in which they occur, and represent a concentration of some minor constituent of that rock. Concretionary stones include flint, chert, and nodules of impure limestone which sometimes occur in clay. ]]></note></mads>