[DnD 3.5 Prestige Class]Crystal Spawn (Need Class Skill advice, kthx.)

[Drakevarg]

Churned this class up recently for no particular reason, but it occured to me that it doesn't have any class skills. And personally, I can't decide which ones to use, so I thought I'd just throw it up here and get a public opinion.

CRYSTAL SPAWN
Hit Dice: d8

Prerequisites
Special: Obtain a Crystal Seed.

Class Skills
-Concentration (CON)
-Craft (INT)
-Heal (WIS)
-Knowledge (Arcana) (INT)
-Knowledge (Nature) (INT)
-Use Magic Device (CHA)
Skill Points: 2

Class Features
Proficiencies:
-All Simple Weapons
-All Martial Weapons
-All Armor
Crystal Armor: A Crystal Spawn can generate a cystalline carapace over any armor he is already wearing at will, which grows as he levels up. This armor takes a full-round action to generate, and another to retract. When generated, the armor gives the Crystal Spawn a Natural Armor Bonus equal to his class level, and Damage Reduction/Bludgeoning equal to half his class level, rounded down.
Crystal Arrows: A Crystal Spawn can generate a crystalline version of any ranged weapon lacking moving parts, or the ammunition thereof. (For example, a Crystal Spawn could generate a javelin or an arrow, but not a longbow.) Doing so requires a move action, and the generated item shatters into worthless dust one round after leaving the Crystal Spawn's posession. The generarated items have the same stats as the basic items found in the Player's Handbook.
Crystal Blade: At 3rd level, the Crystal Spawn gains the ability to generate a crystal version of any melee weapon lacking moving parts. Doing so requires a full-round action, and the generated item shatters into worthless dust one round after leaving the Crystal Spawn's posession. The generated items have the same stats as the basic items found in the Player's Handbook.
Arcane Absorbtion, Lesser: At 5th level, the Crystal Spawn becomes naturally attuned to arcane energy. Any time he is struck by a spell that deals either cold or fire damage, the energy is absorbed and temporarily enhances the Crystal Spawn's armor and weapons. This effect lasts for 10 rounds. Depending on the type of energy he is struck with, the Crystal Spawn gains one of two abilities;
Sapphire Form: If the Crystal Spawn is struck by a spell that deals cold damage, his armor and any generated weapons turn blue. (As opposed to the normal clear coloration.) When this occurs, the Crystal Spawn's Crystal Armor gains Cold Resistance 10, and any weapons generated (melee or ranged) deal an additional 1d6 cold damage. If Ruby Form is activated when the cold spell hits, it is deactivated when Sapphire Form activates.
Ruby Form: If the Crystal Spawn is struck by a spell that deals fire damage, his armor and any generated weapons turn red. When this occurs, the Crystal Spawn's Crystal Armor gains Fire Resistance 10, and any weapons generated (melee or ranged) deal an additional 1d6 fire damage. If Sapphire Form is activated when the fire spell hits, it is deactivated when Ruby Form activates.
Obsidian Edge: At 7th level, any slashing or piercing weapon generated by the Crystal Spawn's Crystal Blade ability is treated as Keen, doubling the weapon's threat range. At the same time, the Crystal Spawn gains the ability to coat his non-crystal weapons in crystal, giving any piercing and slashing weapons the same Keen ability and subject to the Arcane Absorbtion bonuses. Like generated weapons, this crystal coating shatters into dust one round after leaving the Crystal Spawn's posession.
Arcane Absorbtion, Greater: At 9th level, the Crystal Spawn becomes even more succeptable to arcane energies. Greater Arcane Absorbtion functions identically to Lesser Arcane Absorbtion, but the new forms function as follows;
Sapphire Form: If the Crystal Spawn is struck by a spell that deals cold damage, his armor and any generated weapons turn blue. When this occurs, the Crystal Spawn's Crystal Armor gains Cold Resistance 20, and any weapons generated (melee or ranged) deal an additional 1d6 cold damage. Additionally, in the event of a critical, the enhanced weapon deals an additional Xd10 cold damage, where X = the weapons critical multiplier -1. If Ruby Form is activated when the cold spell hits, it is deactivated when Sapphire Form activates.
Ruby Form: If the Crystal Spawn is struck by a spell that deals fire damage, his armor and any generated weapons turn red. When this occurs, the Crystal Spawn's Crystal Armor gains Fire Resistance 20, and any weapons generated (melee or ranged) deal an additional 1d6 fire damage. Additionally, in the event of a critical, the enhanced weapon deals an additional Xd10 cold damage, where X = the weapons critical multiplier -1. If Sapphire Form is activated when the fire spell hits, it is deactivated when Ruby Form activates.

The Crystal Spawn
{table=head]Level|Base Attack Bonus|Fort Save|Ref Save|Will Save|Natural Armor Bonus|

Special

1st

|

+0

|

+2

|

+0

|

+0

|

+1

|

Crystal Arrows

|

2nd

|

+1

|

+3

|

+0

|

+0

|

+2

|Damage Reduction 1/Bludgeoning

3rd

|

+2

|

+3

|

+1

|

+1

|

+3

|

Crystal Blade

|

4th

|

+3

|

+4

|

+1

|

+1

|

+4

|Damage Reduction 2/Bludgeoning

5th

|

+3

|

+4

|

+1

|

+1

|

+5

|

Lesser Arcane Absorbtion

|

6th

|

+4

|

+5

|

+2

|

+2

|

+6

|Damage Reduction 3/Bludgeoning

7th

|

+5

|

+5

|

+2

|

+2

|

+7

|

Obsidian Edge

|

8th

|

+6/+1

|

+6

|

+2

|

+2

|

+8

|Damage Reduction 4/Bludgeoning

9th

|

+6/+1

|

+6

|

+3

|

+3

|

+9

|

Greater Arcane Absorbtion

|

10th

|

+7/+2

|

+7

|

+3

|

+3

|

+10

|Damage Reduction 5/Bludgeoning[/table]

[onthetown]

Not sure if I have the right feel for the flavour of this, but for class skills... Concentration seems like it would be useful because of the full round for some of the abilities. Heal is always useful, and to enter into the class they should probably have Knowledge (Arcana)... Alternatively, you could say that they need Knowledge (Nature) to find a Crystal Seed.

[Drakevarg]

Editted based on your suggestions. Thank you.

I generally prefer to get 8 class skills on any given class. Any other ideas?