Quark stars and quark super nova

Was reading today about the concept of “degeneracy” for various subatomic particles, which among other things explains the properties of white dwarf stars (electron degeneracy) and neutron stars (neutron degeneracy).  Mention was made in the article about quark stars – a hypothetical type of star that basically consists of quark matter bound by gravity (instead of by the strong nuclear force as quarks normally are), as a result of quark degeneracy.

This is extremely weird and there are no established instances of such stars if they exist, although the article mentions there are a couple of candidates which have been observed by Chandra.

Mention is also made of the possibility of quark nova which, if they occur, would be the most powerful explosions in the universe.