Genesis limits

[Zsaber0]

The Artifice spell Genesis says that it can't create life or create buildings, but beyond that "You determine the environment in the demiplane, reflecting most any desire you can visualize, such as atmosphere, water, temperature, and the shape of the terrain." Does this mean that the demiplane that you create could be made of diamond and adamantine ore? Or fields of rare and special herbs or sun orchids?

[Psyren]

That spell is from Pathfinder Campaign Setting, which is actually a 3.5 source - note the year at the bottom of the entry, 2008, which is a year before Pathfinder was released as a standalone game.

In Pathfinder, Genesis was replaced entirely with the Create Demiplane (http://www.d20pfsrd.com/magic/all-spells/c/create-demiplane/) line of spells, which are a bit more restrictive as far as what you can make.

[Zsaber0]

Normally I would agree with you, but the campaign I'm in uses genesis.

[Psyren]

Then you need to discuss with your GM, as there's no RAW answer for how what is essentially a third-party spell is intended to function; it was designed for a different game.

[Eldonauran]

The Artifice spell Genesis says that it can't create life or create buildings, but beyond that "You determine the environment in the demiplane, reflecting most any desire you can visualize, such as atmosphere, water, temperature, and the shape of the terrain." Does this mean that the demiplane that you create could be made of diamond and adamantine ore? Or fields of rare and special herbs or sun orchids?

I'd have to say ... no. Rare and special herbs are plant life, and beyond the scope of the spell. Also, determining WHAT the terrain is made out of is vastly different than determining the SHAPE of the terrain. While it doesn't exactly tell you that you can't do it, it doesn't exactly tell you that you can, either. Take the terrain issue up with the DM, though you and I know that he is likely to tell you no anyway.

[Sagetim]

Genesis has been around for a while. I remember first reading it in 3.0 psionics, as a 9th level power for Metacreativity. It persisted as a psionic power with the Expanded Psionics Handbook, and eventually someone at wizards of the coast noticed that psions could actually do something that there wasn't a wizard spell for, and decided that since psions aren't allowed to have nice things of their own, they would make a spell for Demiplane as well.

So it's been around in 3.5 for a while, though I don't know if there are any differences between it and whatever one might have appeared in the Pathfinder Campaign Setting.

Since we seem to be talking about the 3.5 version of it, while it does not specify a restriction against saying something like 'I make a demiplane with diamond for ground and pools of liquid adamant where the clouds are made of Belladonna*', there are enough implied rules in other spells that trying to get away with that is likely to get you a 'no' from your DM. For example, Wish has a limit of 25k of gp worth of nonmagical stuff per casting, and that also costs 5k xp and is also a 9th level spell (with an admittedly much shorter casting time). While it is not a specified restriction in the rules of the spell/psionic power as it's written in 3.5, you should probably expect similar limits to be imposed unless your DM is willing to just roll with shenanigans.

Edit: Oh, and Genesis can be found on the SRD, in case anyone was wondering.
*if it's not apparent, I'm talking about clouds of poison, not clouds composed of flowers/plants, which the spell species as a no-go.