Shiva Purana
संशोध्य च जलेनापि पिंडीकृत्य शनैः शनैः । विधीयेत शुभं लिंगं पार्थिवं वेदमार्गतः ९ ।
After washing the clay clean with water and kneading it slowly he shall prepare a good earthen phallic image according to the Vedic direction.
english translation
saMzodhya ca jalenApi piMDIkRtya zanaiH zanaiH । vidhIyeta zubhaM liMgaM pArthivaM vedamArgataH 9 ।
hk transliteration by Sanscript