in form, due to the large clusters of crystals which adhere to the unreacted quartz. This clustering results in a dark blue color that is the appearance of coarse Egyptian blue. Alternatively, fine-textured Egyptian blue consists of smaller clusters that are uniformly interspersed between the unreacted quartz grains and tends to be light blue in color. Diluted light blue, though, is used to describe the color of fine-textured Egyptian blue that has a large amount of glass formed in its composition, which masks the blue color, and gives it a diluted appearance. It depends on the level of alkali added to the mixture, so with more alkali, more glass formed, and the more diluted the appearance. This type of Egyptian blue is especially evident during the eighteenth dynasty and later, and probably is associated with the surge in glass technology at this time. If certain conditions were not met, the Egyptian blue would not be satisfactorily produced. For example, if the temperatures were above 1050 °C, it would become unstable. If too much lime was added, wollastonite (CaSiO3) forms and gives the pigment a green color. Too much of the copper ingredients results in excesses of copper oxides cuprite and tenorite. Sources The main component of Egyptian blue was the silica, and quartz sand found adjacent to the sites where Egyptian blue was being manufactured may have been its source, although no concrete evidence supports this hypothesis. The only evidence cited is by Jakcsh et al., who found crystals of titanomagnetite, a mineral found in desert sand, in samples collected from the tomb of Sabni (sixth dynasty). Its presence in Egyptian blue indicates that quartz sand, rather than flint or chert, was used as the silica source. This contrasts with the source of silica used for glass-making at Qantir (New Kingdom Ramesside site), which is quartz pebbles and not sand. It is believed that calcium oxide was not added intentionally on its own during the manufacture of Egyptian blue, but introduced as an impurity in the quartz sand and alkali. As to whether the craftsmen involved in the manufacture realized the importance of adding lime to the Egyptian blue mixture is not clear from this. The source of copper could have been either a copper ore (such as malachite), filings from copper ingots, or bronze scrap and other alloys. Before the New Kingdom, evidence is scarce as to which copper