This can only acquire when you reach Serendipity on the first time, talk to Mystic and she will give you Mog's Manifestation which can improve your moggle's throw and Haggler skill to increase your sale price by 10%. Do this moggle throw at certain areas to get one of a kind monster crystal.

Crystal	How to unlock
Cactuarama	A Dying World 700 - Throw Mog on to position close to Chocolina in the black sands zone.
Cactuarina	New Bodhum 003AF - Throw Mog into the crater beneath the gate in the meteorite impact site area.
Chichu	Archylte Steppe ???AF - Throw Mog into the patch of red flowers close to the cactuar waystone on the plains of eternity.
Leyak	Sunleth Waterscape 300AF - Hurl Mog at the two Miniflan while riding the giant beast in the anime trail area.
Nanochu	Archylte Steppe ???AF - Throw Mog onto the small island at the center of the clearwater marshes. The probability of finding the Nanochu crystal is 10%
Rangda	New Bodhum 003AF - Throw Mog into the ocean from the pier east of the NORA house.
Silver Chocobo	Academia 4XXAF - Throw Mog onto the platform beneath the holographic projection of Cocoon.