These are 4 iron nails inscribed with Quranic verses from Indian/Persian region. These square-sided nails are made of iron with one end is sharp whereas the other end is blunt.
It is typical for houses especially in Northern India and border to Persia, these nails were driven normally at the corners of the building with the purpose of providing protection from evil spirits.
In an auction of Sotheby's London in its 'Arts of the Islamic World', October 13, 2004, similar nails were estimated of £6,000-£8,000.
Dim : 140mm x 10mm
Date : 19th Century CE
Material : Iron
Origin : Indo Persian