Skandapurana 1.4.11.157

1.4.11.157

varuṇaḥ sphāṭikaṃ liṃgaṃ nāmnā ca parameśvaram..
nāgā vidrumaliṃgaṃ ca nāma lokatrayaṃkaram.. 13.157 ..

Varuṇa, a crystal liṅga, and the name “Parameśvara”;
the Nāgas, a coral liṅga, and the name “Creator of the Three Worlds”;