Each necklace features a special stone and will be made of real gold or silver. They are up for reservation now and will be released December 2nd, 2014.
Silver Pikachu with Citrine stone - 15,000 yen
Gold Pikachu with Citrine stone - 49,000 yen
Eevee with White Topaz stone - 15,000 yen
Mew with Pink Topaz stone - 15,000 yen
Espeon and Umbreon with Quartz stone - 22,000 yen