Quezon city: The Northern Samar provincial government is boosting its awareness campaign on the Biri Rock Formations, dating back about 23.03 to 17.95 million years. For weeks, museum visitors at the University of the Philippines Diliman have been introduced to the province's remarkable geological heritage through an exhibit featuring the famed Biri Rocks alongside rare rock specimens from various parts of Northern Samar.

According to Philippines News Agency, highlights of the exhibit include: analcime clasts and analcime sandstone from Biri town; retinite and fossil wood from Lope de Vega; and Allen phonolite from Barangay Balicuatro in Lavezares town. 'The analcime sandstone of Biri is considered the only known occurrence of analcime-rich sandstone in the Philippines. Distributed within Biri Island, it dates back to the Early Miocene period (23.03-17.95 million years ago), based on calcareous nannofossil evidence,' the provincial government said in a statement Monday.

Meanwhile, the Allen phonolite is the second reported alkaline volcanic rock in the country. Found in the municipalities of Allen and Lavezares, it dates to the early Middle Miocene, about 14.2 to 15.98 million years ago, marking a significant volcanic phase.

Designated as the Philippines' seventh National Geological Monument, the Biri Rock Formations underscore the country's outstanding geoheritage and strengthen Northern Samar's bid to join the UNESCO Global Geopark network. The exhibit was enabled by the joint efforts of the provincial government, the National Committee on Geological Sciences, the National Institute of Geological Sciences (NIGS), and the Nannoworks Laboratory.

The 'Biri Rocks!!!' exhibit runs from April to May 2026 at the NIGS- University of the Philippines Geology Alumni Association Geology Museum in Quezon City.