Shiva Purana
रत्नजं हेमजं लिंगं पारदं स्फाटिकं तथा । पार्थिवं पुष्परागोत्थमखंडं तु प्रकारयेत् २९ ।
Whether it is made of gems, gold, mercury, crystals or Pusparāga it shall be a single whole.
english translation
ratnajaM hemajaM liMgaM pAradaM sphATikaM tathA । pArthivaM puSparAgotthamakhaMDaM tu prakArayet 29 ।
hk transliteration by Sanscript