This information is taken from the Japan Masterwiki, I've posted as a guideline to what is needed and will be updating as soon as the mats needed in the EU/NA version can be confirmed.
|White Knight Chronicles II » Geoforging » Gems/Elemental Stones|
- The recipes are calculated as they appear in your guild, and could be different from day to day. They will always be the same equation though, if recipe is Normalx1 + Hardx1, it could involve any combination of 1 Normal and 1 Hard.
 Gems/Elemental Stones
|Item||Number Made||Geostone 1||Geostone 2||Geostone 3|
|Chromium Gem Lv. 9||1||Rare x3||Rare x2|
|Guardian Gem Lv. 9||1||Rare x3||Rare x2|
|Chromium Gem Lv. 7||3||Aries Quartz x2||Scorpio Gem x2|
|Guardian Gem Lv. 7||3||Gemini Quartz x2||Libra Gem x2|
|Flame Crystal||3||Libra Gem x2||Aries Quartz x2|
|Gale Crystal||3||Scorpio Gem x2||Aries Quartz x2|
|Terra Crystal||3||Gemini Quartz x2||Sagittarius Gem x2|
|Rain Crystal||3||Gemini Quartz x2||Aries Quartz x2|