stone fist and animal aspect (gorilla) stackable?

[Quinn Muldarra]

If you cast stone fist then animal aspect (gorilla) would that increase your d6 unarmed damage to d8s? Are they stackable?

[Nefreet]

For reference, Stone Fist and Animal Aspect:

Stone Fist wrote:

School transmutation [earth]; Level alchemist 1, druid 1, sorcerer/wizard 1

Casting Time 1 standard action
Components V, S, M (a chip of granite)
Range personal
Target you
Duration 1 minute/level (D)

This spell transforms your hands into living stone. While this spell is in effect, your unarmed strikes do not provoke attacks of opportunity and deal 1d6 points of lethal bludgeoning damage (1d4 if you are Small). In addition, your unarmed strikes ignore the hardness of any object with a hardness less than 8.

Stone to flesh immediately dispels stone fist. Should you be the target of transmute rock to mud, this spell immediately ends and you take 4d6 points of damage.

Animal Aspect (Gorilla) wrote:

School transmutation (polymorph); Level alchemist 2, magus 2, druid 2, ranger 2, sorcerer/wizard 2

Casting Time 1 standard action
Components V, S, M/DF (a part of the animal)
Range personal
Target you
Duration 1 minute/level (D)
Saving Throw none; Spell Resistance yes (harmless)

You gain some of the beneficial qualities of an animal. Your base form is largely unchanged and your size is unaltered, but some of your body parts are altered. Armor or gear you are wearing adjusts to your new shape for the duration of the spell. When you cast animal aspect, choose one of the following animals to gain the associated benefits. You can only have one animal aspect or greater animal aspect spell active on you at a time.

Gorilla: Your arms become long, flexible, and strong like those of a great ape. Your unarmed damage die type increases by one step, and you gain a +4 competence bonus on combat maneuver checks when making the grapple or reposition combat maneuver.

I would say they stack. One spell gives you a base 1d6, and the next spell increases whatever you have by one step, which in this case would become 1d8.

Although both spells are of the Transmutation School, only one is of the Polymorph Subschool.

[Dolanar]

I am not seeing anything wrong with it from a quick glance.