The concept of Significant Properties is one which has been much discussed within the preservation community as a way of characterising the essential features of a digital object which must be maintained over time. However, the term Significant Properties has been given a variety of definitions and used in various ways over the past several years. There is also a lack of consensus on how Significant Properties are categorised and tested. Furthermore it is unclear how the concept applies to scientific data. In this paper we discuss the new proposed definitions in the revision of OAIS, and draw together and provide a coherent view of Significant Properties, Authenticity, Provenance and Representation Information.