How was the calf made?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. Al-Sāmirī was a goldsmith, so he crafted the calf and cast a handful of earth into (the melting pot) (see v. 20:96). [ʿAlī, Ibn ʿAbbās]
2. They dug a pit and threw into it the jewelry of the people of Pharaoh and their borrowed items to purify themselves from it. Al-Sāmirī then cast a handful of earth into it, and it became a calf. A report from Ibn ʿAbbās states that it became flesh, blood, and a body. Al-Sāmirī then told them, "This is your god and the god of Mūsā who has come, but Mūsā lost his way." So they worshipped it and danced around it.