<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31344504</termId><termName>opal</termName><termType>PT</termType><termNote><![CDATA[ A mineral or mineral gel consisting of packed spheres of silica. Used as a gemstone, it is characterized by a flashing mixture of colors when light falls on the surface. ]]></termNote><termCreatedDate>2026-03-30 20:32:54</termCreatedDate><relation><relationType>UF</relationType><termId>31344505</termId><termName>opals</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31320469</termId><termName>mineral</termName><termType>PT</termType></relation><relation><relationType>BT</relationType><termId>31376754</termId><termName>gemstones by specific type</termName><termType>PT</termType></relation></term>  </Zthes>