frit may be slightly higher than that of blue frit, in the range of 950 to 1100 °C. The ultimate product is composed of copper-wollastonite ([Ca,Cu]3Si3O9) crystals and a "glassy phase rich in copper, sodium, and potassium chlorides". In certain circumstances (the use of a two-step heating process, the presence of hematite), scientists were able to make a cuprorivaite-based blue frit that later became a copper-wollastonite-based green frit at a temperature of 1050 °C. On some ancient Egyptian wall paintings, pigments that were originally blue are now green: the blue frit can "devitrify" so that the "copper wollastonite predominates over the lesser component of cuprorivaite". As with blue frit, Hatton, Shortland, and Tite have analyzed evidence for green frit at Amarna in the form of cakes, powders, and one vessel fragment and inferred the sequential production of the three types of artifacts. Relationships between frit, glass and faience An Akkadian text from Assurbanipal's library at Nineveh suggests that a frit-like substance was an intermediate material in the production of raw glass. This intermediate step would have followed the grinding and mixing of the raw materials used to make glass. An excerpt of Oppenheim's translation of Tablet A, Section 1 of the Nineveh text reads: The steps that follow involve reheating, regrinding and finally gathering the powder in a pan. Following the Nineveh recipe, Brill was able to produce a "high quality" glass. He deduced that the frit intermediate is necessary so that gases will evolve during this stage and the end product will be virtually free of bubbles. Furthermore, grinding the frit actually expedites the "second part of the process, which is to … reduce the system to a glass". Moorey has defined this intermediate step as "fritting", "a process in which the soluble salts are made insoluble by breaking down the carbonates, etc. and forming a complex mass of sintered silicates". A frit preserved in a "fritting pan fragment" kept in the Petrie Museum "shows numerous white flecks of unreacted silica and a large number of vesicles where gases had formed". The process was known to ancient writers Pliny and Theophilus. But whether this "fritting" was done in antiquity as a deliberate step in the manufacture of raw glass remains questionable. The compositions of frits and glasses recovered from Amarna do not agree in a way that would imply frits were the immediate precursors of glasses: the frits have