Monazite is a common accessory phosphate mineral that occurs under a wide range of pressure and temperature conditions in sedimentary. metamorphic and igneous rocks. Monazite contains high amounts of Th and U. rendering single monazite grains suitable for in-situ U-Th/Pb dating using laser ablation inductively-coupled mass spectrometry (LA-ICP-MS). https://www.globalspecialtyfoods.com/product-category/puffco-proxy-accessories/