Carbonado in the pores that are common in carbonados, they may have been introduced after carbonado formation. Inclusions of other minerals, rare or nearly absent in the Earth's crust, are found at least partly incorporated in diamond, not just in pores: among such other minerals are those with compositions of Si, SiC, and Fe‑Ni. No distinctive high-pressure minerals, including the hexagonal carbon polymorph, lonsdaleite, have been found as inclusions in carbonados, although such inclusions might be expected if carbonados formed by meteorite impact. Isotope studies have yielded further clues to carbonado origin. The carbon isotope value is very low (little carbon‑13
What Is Life song offers "little overall coherence between words and music". In a 2010 poll to find the "10 Best George Harrison Songs", AOL Radio listeners voted "What Is Life" third behind "My Sweet Lord" and "Blow Away". A similar list by Michael Galluci of Ultimate Classic Rock placed it second (behind "My Sweet Lord"), as Galluci wrote of the track having "a giant pop hook as its guide" as well as "the catchiest chorus Harrison ever penned".<ref name="Gallucci/UCR">Michael Gallucci, "Top 10 George Harrison Songs", Ultimate Classic Rock (retrieved 28 March 2014).</ref> In 2009, Matt Melis of Consequence of Sound listed it