I am looking for a science fiction novel I read at least 16 years ago, when I had a used paperback copy from a library or used book store.
One of the main characters was a person who was part of a military/police organization. He flew a spaceship/personal space suit that I think was described as being made of stone, or a stone like material that was brittle and could be chipped into pieces. During one part of the book, he had to escape his home and used a knife-like weapon (disruptor knife?) that melted people from the inside out if stabbed, and also decayed/melted wooden support beams or similar.
Another main character was some kind of cat person/alien. She ended up being friends with the stone suit guy. I think she was a pilot of some kind. At the end of the book, someone built her a ship of her own, and they flew off together.
I am at least 60% certain the protagonist of the book was some human guy, but I've completely forgotten anything to do with his motivations.
Unfortunately, cat aliens and space suits are common google search results, and I haven't had any luck narrowing it down further.