“STRANGE QUARK STARS may be naked SQM objects wrapped in simple nuclear crusts or bulk SQM nuclei. The possible presence of nuclear crusts creates SSs that are very similar to normal neutron stars for a distant observer.” (SSs = strange quark stars; SQM = strange quark matter); for full reference paste title into Google Scholar.
https://link.springer.com/article/10.1007/s10509-018-3335-9