The National Investigation Agency (NIA) has concluded that a powdered substance recovered from the Uttar Pradesh Assembly on July 12, suspected to have been high-grade explosive PETN, was “quartz,” a material used to make glass and cast metal.Chief Minister Yogi Adityanath had described the recovery as a “dangerous terror conspiracy” and recommended a probe by the NIA. The Home Ministry received a report from the State that the 150 g of powder wrapped in paperwas PETN (Penta-erythritol tetranitrate), an explosive that could have blown up the building.The suspicious powder was found close to the seat of Leader of the Opposition Ram Govind Choudhary.The NIA had sent the samples for forensic examination and the results said the powdered substance was not PETN.“It was quartz or, in common terms, sandstone that is used to make glass. The powdered substance, wrapped in a paper and then a polythene bag, was found stuck under one of the seats,” said a senior NIA official.The official said the polythene bag had been lying there for at least five months. “There was some renovation work undertaken at the Assembly building. It seems the workers who did the renovation, left behind the powdered substance. Since it was stuck under the seat, the cleaners missed it,” the official said.Based on the U.P. government’s request, the NIA had registered a case under the Unlawful Activities (Prevention) Act (UAPA).A team of experts from the Central Forensic Science Laboratory (CFSL), Chandigarh, visited the Assembly building on September 2.The ATS had earlier questioned Samajwadi Party MLA Manoj Pandey in connection with the case as the powdered substance was found close to his seat.