It does not directly state that it is health based. But is very easy to show and can be demonstrated in game. Since pictures are worth a thousand words and there seem to people who would like pics to be shown. I will demonstrate using pictures.
I called up an Abominable Warmaster so I could control the environment (i.e. no other people influencing damage being dealt).
I bought a plain no nano VOT Blaster from a vendor seen here:
My loadout I used was simple and I removed DLC perks:
I shot the WM in the back using the no nano VOT Blaster and got 3905 DMG being dealt:
I added a Fire Converter to the VOT Blaster (which should decrease the Card Damage from 7382 to (0.9 x 7382) to ~ 6643.8. Card shows 6644 so that checks out:
Now if the Warmaster Blue Armor Crystal is health based then the damage done by fire converted Blaster should be 3905 x 0.9 x 1.5 = 5271.75.
So lets see what we got:
We got exactly 5272. Which checks out.
Thus proving without a doubt that the Warmaster Blue Crystal is indeed Health Based.