1. A group of hydrated silicate minerals, typically colorless or white, that form in cavities of volcanic rocks and are valued by collectors.
Usage: mineralogy; plural form; singular is apophyllite

Examples

• Apophyllites are prized by mineral collectors for their brilliant luster and perfect cubic cleavage.
• The geologist identified apophyllites in the basalt samples using X-ray diffraction.
• Apophyllites often occur alongside zeolites in amygdaloidal volcanic rocks.
• The museum's mineral exhibit featured several specimens of apophyllites from India.
• Collectors appreciate apophyllites for their transparency and geometric crystal forms.