The features on this face are closest to portraits of Ptolemy I and Ptolemy II. See for example a red granite statue of Ptolemy II now in the Vatican Museums, no. A3, figs. 2-3 in Stanwick, Portraits of the Ptolemies, Greek Kings as Egyptian Pharaohs, and a basalt statue of Ptolemy I in the British Museum, no. 3 in Walker and Higgs, Cleopatra of Egypt from History to Myth. For an unidentified king with similar features on a limestone sphinx of this date see no. A39, fig. 38 in Stanwick, op. cit. For a faience seated Ptolemaic king in Leiden, see no. 9 in Bianchi, et al., Cleopatra's Egypt, Age of the Ptolemies..
This vitreous material is often mistakenly described as glassy faience. According to Nicholson (p. 55 in Friedman, ed., Gifts of the Nile, Ancient Egyptian Faience), use of the term glassy faience is a misnomer, as it is actually a kind of imperfect glass that contains frit and has no distinctive glaze, being homogeneous throughout. Experts regard the red stain on the left cheek as decomposition of the elements and an indicator of age.