Micro-World Gems & Gemology, Summer 2025, Vol. 61, No. 2

Monazite in Quartz

Rui Rui Xing, Wingtak Lui, and Tsu Wei Chang

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Left: Numerous orange-yellow to orange solid inclusions are visible within the transparent colorless quartz. Right: Closer observation reveals bright orange wedge-shaped crystals. Photomicrographs by Wingtak Lui; fields of view 5.1 mm (left) and 3.2 mm (right).
 
Left: Numerous orange-yellow to orange solid inclusions are visible within the transparent colorless quartz. Right: Closer observation reveals bright orange wedge-shaped crystals. Photomicrographs by Wingtak Lui; fields of view 5.1 mm (left) and 3.2 mm (right).

Recently, several platy orange-yellow inclusions were observed within a highly transparent colorless quartz crystal (see above, left). These inclusions exhibited an orange-yellow to orange color, a smooth surface, and a glassy luster, with a euhedral or subhedral appearance. Closer inspection revealed that some crystals displayed the typical wedge shape of monoclinic crystals (see above, right). This distinct crystal morphology and vibrant color prompted further investigation into their composition.

Raman spectroscopy identified the inclusions as monazite, a phosphate mineral ((Ce,La,Nd,Th)PO4). Further analysis using X-ray fluorescence confirmed a high concentration of cerium, classifying the inclusions specifically as monazite-(Ce).

Rui Rui Xing, Wingtak Lui, and Tsu Wei Chang are affiliated with Min De Minerals & Gem Research Co., Ltd. in Nanjing, China.