HIMT, glass composition and commodity branding in the primary glass industry
Abstract
New elemental data confirm the proposal by Ceglia et al. (2015) of two sub- groups of high iron, manganese and titanium glass, HIMTa and HIMTb, differing in their ratios Fe2O3/ TiO2 and Fe2O3/ Al2O3. Neodymium and strontium isotopes are consistent with south- eastern Mediterranean coastal sand for both groups, allowing for an identifia-ble strontium contribution from the added manganese. Trace elements are consistent with an Egyptian origin, although a marked Eu anomaly in HIMTa is correlated with Ba, again added with manganese. Strong within- group correlations between manganese and iron oxides are not easily explained either as deliberate additions of manganese decol-ouriser or as a characteristic of the glass- making sand. Instead, HIMT glass is considered to have been deliberately tinted yellow- green by the primary glass makers to distinguish it from the green- blue glass of the Levant. The colour branding of the raw glass allowed glass workers to distinguish sodium- rich Egyptian HIMT glass from the more viscous, high working temperature Levantine glass, thereby offering savings in marginal costs, such as those relating to fuel.