ISIS largely destroyed artifacts with explosives and bulldozers and the Christian sites were almost the least of it;

    In 2014, media reported destruction of multiple religious buildings belonging to both Sunni and Shia sects throughout areas captured by IS.

    Among them were the tomb of Ibn al-Athir, Imam Abbas Mosque in Mosul, the Sheikh Jawad Al-Sadiq Mosque, Tomb of Sayyid Ar-Mamut Baba, Qaddo Mosque, Martyrs' Mosque, Saad Ibn Aqeel Shrine in Tal Afar, the Sufi Ahmed al-Rifai Shrine and Sheikh Ibrahim's shrine in Mahlabiya District.

Very old pre Christian sites were also destroyed, but more often looted to sell to collectors to raise money:

    In May 2014, IS members smashed a 3,000-year-old neo-Assyrian statue from Tel Ajaja. Later reports indicated that over 40% of the artifacts at Tel Ajaja (Saddikanni) were looted by IS.

There's a pretty sizable list of what they destroyed and looted in:

https://en.wikipedia.org/wiki/Destruction_of_cultural_herita...

     the group released photos of militants rigging the 1,900-year-old Temple of Baalshamin with explosives and blowing it up. It was one of Palmyra’s best-preserved buildings, originally dedicated to a Phoenician storm god. Now it is nothing but rubble.

https://www.nationalgeographic.co.uk/history-and-civilisatio...