@Chemist
Let’s try this again, with less late-night grammatical horror. Somewhere, a pedant earned his wings because of the original post.
Here’s the revised version:
A Neutron Star is basically a big old lump of neutrons at its center, where the extreme mass has compacted the matter so much that the protons and electrons have combined.
This "neutronium" is highly unstable, and tends to revert to normal matter if it works its way far enough from the core. There are also layers of material that on top of the neutronium that are not under so much gravitational stress as to convert into neutronium. The outer layers of the star probably look relatively normal by comparison.
Neutron stars, being so massive, may also have an accretion disk (much like a black hole.) From where we are, it would be virtually impossible to tell if a given star had an accretion disk or not (the star being powerful enough to outshine the disk) but if it did then that matter spiralling into the star would light the bugger up like a big magnetic candle.
In short: think of a neutron star as very close to a black hole. Unlike a black hole which is so dense as to have an event horizon, neutron stars are just the other side of that barrier. A lot of the weird things that happen near black holes happen near neutron stars. There is the exception that we can almost understand the physics of a neutron star because the entireties of the reactions are occurring on this side of the event horizon.
There is also a theory that a sufficiently massive neutron star could house a micro black hole at its core which would slowly grow in size as it consumed the neutron star from the inside out. Eventually for reasons that I only barely comprehend (and would take way to long to explain) this mixture hits a tipping point and actually /blows up/. (Or more accurately, blows the shell off the whole shebang while imploding, leaving a black hole surrounded by a cloud of gas and an expanding plasma shockwave.)
Then you get into the theories where they have to blow up /before/ becoming black holes. (An implosion wave similar to an implosion nuke compressing the core of the star past the neutronium stage into “oh shit physics broke” and creating a black hole.)
In short: once you start getting neutronium involved, we are approaching the very limit of our understanding of the universe.
For now.
I am sure Steven Hawking has it all figured out; he’s just biding his time until he releases a slew of books that tie our understanding of this mess up nicely. (After he is proven right that black holes evaporate. If he is proven right? Lots of debate there still.)