Force Core (Medium)

Introduction
A comprehensive list of cores can be found here. Force cores are mainly used for socketing options in empty slots, more info can be fond here. Other types of force cores are as follows:
 * Force Core (Low)
 * Force Core (Medium)
 * Force Core (High)
 * Force Core (Highest)

Obtained from

 * Craft: Basic Craft level 7
 * Field: Port Lux, Fort Ruina, Mutant Forest
 * Dungeon: Lake in Dusk, Ruina Station, Tower of the Dead (B1F), Weakened Ruina Station, Weakened Tower of the Dead (B1F), Chaos Arena Lv. 1, Chaos Arena Lv. 2