Yes, might as well stat them up in statue form, especially as it repeatedly says they die if the statue is destroyed rather than floating off to find another stone-carved body.
Definitely Elemental like the Flame Spirit, probably Earth and Extraplanar.
They don't have DR/magic like flame spirits, so do we want to give them DR X/- for their solid stone bodies?
Apart from that, they're basically Small/Medium/Large Earth Elementals with a single attack and the Small ones can have wings. I'm tempted to make the small ones always have wings rather than sometimes.
Let's see, they're a bit more intelligent, have a vulnerability to Earth magic (whatever we decide for that).
So, let's take an Earth Elemental and tweak it. I'd increase the Dex a bit, mainly for a bit of differentiation but also because the Small ones can fly, which suggests a slighting better agility to me.
The "Special Attack: See below" suggests something in the way of special attacks, but their combat entry only makes vague references to them attacking by ramming. Maybe give them Powerful Charge?
How's this for a start:
Stone Spirit, Small
Small Elemental (Extraplanar, Earth)
Hit Dice: 2d8+2 (11 hp)
Initiative: +0
Speed: 30 ft. (6 squares), fly 20 ft. (clumsy)
Armor Class: 15 (+1 size, +4 natural), touch 11, flat-footed 15
Base Attack/Grapple: +1/+0
Attack: Slam +5 melee (1d6+4)
Full Attack: Slam +5 melee (1d6+4)
Space/Reach: 5 ft./5 ft.
Special Attacks: Powerful charge [2d6+6]
Special Qualities: Damage reduction 2/–?, darkvision 60 ft., elemental traits, vulnerability to Earth magic
Saves: Fort +4, Ref +0, Will +0
Abilities: Str 17, Dex 10, Con 13, Int 8, Wis 10, Cha 11
Skills: ?
Feats: ?
Environment: Any land or underground and Elemental Plane of Earth
Organization: Solitary or group (2-8)
Challenge Rating: 1
Treasure: Standard goods (gems only)
Alignment: Usually neutral evil
Advancement: 3 HD (Small)
Level Adjustment: —
Stone Spirit, Medium
Medium Elemental (Extraplanar, Earth)
Hit Dice: 4d8+12 (30 hp)
Initiative: +0
Speed: 20 ft. (4 squares)
Armor Class: 17 (+7 natural), touch 10, flat-footed 17
Base Attack/Grapple: +3/+8
Attack: Slam +8 melee (1d8+7)
Full Attack: Slam +8 melee (1d8+7)
Special Attacks: Powerful charge [2d8+10]
Special Qualities: Damage reduction 3/–?, darkvision 60 ft., elemental traits, vulnerability to Earth magic
Saves: Fort +7, Ref +1, Will +1
Abilities: Str 21, Dex 10, Con 17, Int 10, Wis 10, Cha 11
Skills: ?
Feats: ?
Environment: Any land or underground and Elemental Plane of Earth
Organization: Solitary or group (2-4)
Challenge Rating: 3
Treasure: None
Alignment: Usually neutral evil
Advancement: 5-7 HD (Medium)
Level Adjustment: —
Stone Spirit, Large
Large Elemental (Extraplanar, Earth)
Hit Dice: 8d8+32 (68 hp)
Initiative: +0
Speed: 20 ft. (4 squares)
Armor Class: 19 (-1 size, +10 natural), touch 9, flat-footed 19
Base Attack/Grapple: +6/+17
Attack: Slam +12 melee (2d8+7)
Full Attack: Slam +12 melee (2d8+7)
Space/Reach: 10 ft./10 ft.
Special Attacks: Powerful charge [4d8+14]
Special Qualities: Damage reduction 5/–?, darkvision 60 ft., elemental traits, vulnerability to Earth magic
Saves: Fort +10, Ref +2, Will +2
Abilities: Str 25, Dex 10, Con 19, Int 10, Wis 10, Cha 11
Skills: ?
Feats: ?
Environment: Any land or underground and Elemental Plane of Earth
Organization: Solitary
Challenge Rating: 5
Treasure: None
Alignment: Usually neutral evil
Advancement: 9-15 HD (Large)
Level Adjustment: —