Getting there! With the current load of class features, I'd recommend you compress this into a five-level class. The concept of "hunts heretics and stabs them with a magic crystal sword" is really very narrow.
If you'd like to preserve it as a 10-level class, you need more class features. First, a look at what you have:
Crystal Blade: This is not really a class feature, but you knew that. The name implies that the blade is made of crystal, but if it is, you're basically inventing a new material (weapon-grade crystal), and you should specify its break DC, hardness, and hp.
Smite the Unfaithful: fixes many of the defects of Smite Evil. Good.
Track: Thematic feat is thematic.
Crystal Skin: Is the bonus intended to be untyped, rather than an enhancement bonus to natural armor?
Crystal Blade Bonus: I take you to mean that the owner can apply enhancement bonuses to the weapon, or special abilities that are priced as enhancement-bonus-equivalents. I like the flexibility this offers (Need a different special ability? Spend a move action and you have it!). Overall, however, this is weak ability. Compare to a kensai's ability, which allows a total +10 enhancement over a 10-level prestige class. And nobody gets excited about the kensai unless they're enhancing some dwarf's beard.
Now, a look at what you haven't got. Providing Track with Crystal Skin at level 2 is basically an admission that +1 natural armor alone isn't a strong enough benefit to carry a level, yet that's exactly what you then proceed to do at levels 4, 6, 8, and 10. If anything, you need something better at these levels because the character is higher level at this point and needs more razzle-dazzle.
Benefits I would suggest:
- Favored-enemy style skill bonuses against hunted foes, perhaps applicable to Hide, Move Silently, Spot, Listen, and Survival.
- The ability to use Dexterity instead of Strength to calculate hit and damage with simple and light weapons.
- Automatic TWF progression (a no-brainer in a martial class with sufficient bonus natural armor to obviate the need for a shield, that only uses light martial weapons, intended for a race with a Dex bonus).
- Faster advancement of crystal blade bonus (or perhaps just a higher starting bonus), so the enhancements will duplicate magic weapons more appropriate to the ECL of the wielder.
- Improvements to the hunting and wilderness survival roles, such as flawless stride, swift tracker, camouflage, hide in plain sight, or abilities that are thematically similar to those.