Gem-generating globals

[magnate]

Not sure if I'm being thick, or whether there isn't a global enchantment that produces nature gems. I've found the following:

Gale Gate (Thaum 8, Air 5, cost 60 air) - 20 air gems/turn
Eternal Pyre (Ench 6, Fire 6, cost 80 fire) - 20 fire gems/turn
Stellar Focus (Ench 7, Astral 5, cost 30 astral) - 5 astral pearls/turn
Earth Blood Deep Well (Ench 7, Earth 6, cost 80 earth) - "lots" of earth gems/turn
Maelstrom (Evoc 8, Water 6, cost 80 water) - "huge numbers" of water gems/turn
Well Of Misery (Conj 8, Death 6, cost 80 death) - "truckloads" of death gems/turn

... but I can't find anything for nature gems (or blood slaves, natch). Am I missing something?

Also, does anyone know the "huge" numbers for the last three listed? Are they all 20?

TIA,

CC