Water gem

Water gems (玉水石, Tamamizu) are an item mentioned in supplementary materials for Suikoden II.

Information
Water gems are a precious form of gem that is seemingly only found in the Tinto Mines. This ore can be used in the creation of tools and magical contraptions related to runes. They can also be used to assist in performing powerful magic. It is through the sale of water gems to other nations in particular that a region like Tinto Principality can fund its powerful army.