Geode (Item)
A Geode is an item that may be used by Earth ponies to grow gems via the Farming Talent. The Geode will be harvestable after a certain amount of time. The amount of time depends on the Farming level.
Geodes are not planted in farm plots like Crops and Flowers, instead a pony must hold them in their inventory. An unknown formula decides how fast gems grow. The pony must be logged in for the gems to grow. The maximum amount of gems from a single Geode is affected by Farming level. The formula is not linear, meaning its not the same time for each additional gem to grow. The growth time of the first gem is not affected by the gem type and is only affected by farming level.
Farming level 50 increases the growth by a lot, making it possible to get the maximum amount of gems about 6 times faster than level 36. (Confirmation needed)
The Aquamarine however does not grow as fast as the other gems and the maximum amount you can get from 1 geode is way less than other gems.
The gem rarity from most common to most rare is as follows: Topaz = Ruby < Bloodstone = Moonstone < Diamond < Emerald = Peridot = Sapphire < Aquamarine = Citrine (Onyx was most likely mentioned instead of Peridot, as Peridots can be obtained and Onyxes dont seem to be obtainable(Confirmation needed))
Garnets are currently unobtainable from Geodes.
Additional information about the formula:
The formula is logarithmic.