Geodes (can someone help me understand)

[Zinato]

The common understanding is

Geodes - Are affected by TH. Can drop at a low rate from any experience wielding mob on day of the week, chances during matching weather are multiplied roughly by 10. Weather always takes priority over day of the week. Additionally, they drop on the seal system, in other words only one per party per 5 minute period. Personal experience shows roughly a 2% drop rate on day, typically 1-2 per game day of farming and 3-4 with TH.

Avatarites - Drop from any mob over the level of 80, they follow the same basic drop rate and rule of geodes. However, additionally they drop on a separate timer then geodes. They do however, take priority in a situation where both could drop. (If you just got to a zone you will see a -rite before a geode drops)

Additional tips -
Light - can be found frequently in Nyzul and in Temnos Limbus
Dark - Mire and Castle Zvahl (both past and present)
Fire - Rarely farmed in Altepa, Terrigan and Yhoator Jungle (for the most part these are only found on matching day)
Wind - Grauberg, Thickets/Woodlands
Water - Boyada Tree and Pashhow (beaudeux)
Ice - Anywhere in the northlands nearly all the time
Earth - Altepa, Attowa and Mount Zhaloym
Lightning - Vunkerl, Boyada tree and Qufim Island
(with exception to light/fire -rites can often be found in the same locations as geodes)

There are other places but, these are the most fruitful for me. Happy hunting.