I got some caked NaBH4. How decomposed is it approximately?

The local chemical manufacturer here sold me a lumpy NaBH4 that's hard to break. It still fizzes a bit in water but somehow my reductions are stalling/falling and I'm wondering if this could be the culprit.

It's still white but hard and lumpy. Just wondering if someone here has experience working with such hard NaBH4 rocks.

What do you think?