SB 10.50.55
syamaika-varnan varuno
hayan suklan mano-javan
astau nidhi-patih kosan
loka-palo nijodayan
Translation:
Lord Varuna offered horses as swift as the mind, some of which were pure dark-blue, others white. The treasurer of the demigods, Kuvera, gave his eight mystic treasures, and the rulers of various planets each presented their own opulences.
Purport:
Srila Sridhara Svami comments as follows on this verse: “The master of the treasury is Kuvera, and the eight treasures are his nidhis. These are described as follows:
padmas caiva mahapadmo
matsya-kurmau tathaudakah
nilo mukundah sankhas ca
nidhayo ’stau prakirtitah
‘The eight mystic treasures are called Padma, Mahapadma, Matsya, Kurma, Audaka, Nila, Mukunda and Sankha.’”