Shiva Purana

siva.sh/siva-purana/rudra-samhita/101/18

महाद्वारि स्थितौ नन्दी कृत्रिमश्च कृतो मुने ।। शुद्धस्फटिकसंकाशो यथा नन्दी तथैव सः ।।१८।।

sanskrit

O sage, the statue of Nandin, at the portals, of crystalline purity and brilliance, was a prototype of the real Nandin.

english translation

mahAdvAri sthitau nandI kRtrimazca kRto mune || zuddhasphaTikasaMkAzo yathA nandI tathaiva saH ||18||

hk transliteration by Sanscript