Is it permissible to buy a leather sofa even though you don’t know what animal the skin has been derived from?
In the name of Allah, Most Compassionate, Most Merciful,
The basic ruling with regards to leather is that, with the exception of pig-skin, the skin of all other animals is considered to be pure (tahir) when it goes through the process of tanning, even if the animal is unlawful to consume (such as a lion), or the animal was not slaughtered according to the rules of Shariah. Pig, however, is considered to be completely filthy; hence its skin remains impure (najis) even after tanning.
Imam al-Quduri (Allah have mercy on him) states:
“Any skin which has been tanned has become clean, hence prayer is valid on it, and wudu from it – except the skin of a pig and human (m: human skin due to its honour).” (al-Lubab fi sharh al-Kitab, 1/47)
Therefore, it will be permitted for one to wear jackets, coats, shoes, use sofas and keep a wallet made from the skin of all animals except a pig. It will not be permitted to wear shoes or clothing from pigskin, and prayer in such items would be invalid.
Thus, it will be permitted for you to purchase leather sofas, as long as you avoid leather made from pigskin.
And Allah knows best
[Mufti] Muhammad ibn Adam
Leicester , UK