Appendix I Archaeometallurgical Waste Thilo Rehren Iron metallurgy (definite and probable identifications) 001 Ek-A 118 (see Fig. 16.13) • Optical microscopy conducted • Polished block analysis: Sample contains numerous pieces of iron slag. Sample also contains material which looks like sandstone/quartzite/rock/granite. It is possible that this material could be furnace building material, for example a furnace wall fragment. Areas of iron slag are stuck onto the material hypothesized as furnace building material. Evidence also of skeletal magnetite which indicates a somewhat more oxidising stage than one would expect for iron smelting, but which is often seen near furnace walls. FIGURE I.1 Archaeometallurgy sample 004 Ek-A 103. Summary comments: The sample appears to relate to fur- • nace wall material with bits of iron slag attached, most likely smelting slag, though this identification of smelting is not 005 Ek-A 96 definite. • Optical microscopy conducted • Polished block analysis: Lots of slag with interesting inclu- 002 Ek-A 114 (see Fig. 16.1) sions. Blocky fayalite and skeletal fayalite in a glassy matrix. • Optical microscopy conducted Magnetite dendrites 2nd generation. Wüstite aggregates/ • Polished block analysis: Iron slag with feathery fayalite. dendrites. Not homogenous but consists of different phases First and 2nd generation wüstite. Stuck onto rock of what (multi-phased) – maybe an oxidation feature. Nothing in appears to be most likely a furnace wall fragment. Abundant terms of sulphides or metals which would indicate copper magnetite crystals. Incorporated sand grains. Mostly glassy smelting. Sand consisting of quartz. Wüstite in the process matrix. of being oxidised to magnetite; possibly this is a tap slag (i.e. Summary comments: The sample appears to relate to fur- flown out of a furnace) which would explain the oxidation. • nace wall material with bits of iron slag attached, most likely Slightly unusual is the sand included but this can occur in smelting slag, though this identification of smelting is not dry environments such as Essouk, when the fluid slag flows definite. over dry sand. • Summary comments: This looks to be iron smelting rather 004 Ek-A 103 than smithing, though this conclusion is not indisputable. • Optical microscopy conducted • Polished block analysis: Iron slag. Rich in wüstite in a fayalitic matrix. Fayalite crystals small and elongated. Silica rich rim with recrystallised silica inclusions (sandstone?). • Summary comments: Potentially smelting slag, but could also be smithing. FIGURE I.2 Archaeometallurgy sample 005 Ek-A 96. © koninklijke brill nv, leiden, ���7 | doi ��.��63/9789004348998_035 Archaeometallurgical Waste 371 006 Ek-A 96 • Optical microscopy conducted • Polished block analysis: Skeletal fayalite in a glassy matrix. Incorporated sand grains. ‘Tap lines’ (where one flow of slag flowing out of the furnace creates a contact zone with the previous flow). Wüstite/magnetite dendrites; 1st genera- tion – 20% by vol (quite high). Locally iscorite developing; normally indicates non-ferrous metallurgy but with a tap slag can also get this with the oxygen coming in during tap- ping. No sulphides or metal indicating copper. • Summary comments: Iron tap slag which looks to be more like smelting than smithing. This conclusion is based upon the flow texture and the amount and nature of iron oxide, FIGURE I.4 Archaeometallurgy sample 007 Ek-A 96. shape and nature of fayalite. Again, slightly unusual is the sand included, though again it is noted that one can get this in dry environments such as Essouk. 009 Ek-A 96 (see Fig. 16.1) • Optical microscopy conducted • Polished block analysis: Layers upon layers of very thin run- ning slag. Tap slag with a spinifex texture. Spinifex in the cen- tre with lower and upper surfaces smooth texture – a typical feature of tap slag. Skin oxidation layer on the top, forming magnetite in contact with air. Slightly puzzling are possible hammerscale fragments, but these could come from superfi- cial burning of the iron tools used to rake out the slag. • Summary comments: Straightforward bloomery smelting tap slag. 010 Ek-A 96 • Optical microscopy conducted • Polished block analysis: Ceramic matrix; cracked quartz FIGURE I.3 Archaeometallurgy sample 006 Ek-A 96. grains. Some areas rich in fayalite. • Summary comments: Iron metallurgy. Smelting related. Looks like piece of furnace wall contaminated with smelting 007 Ek-A 96 slag (fragment of charcoal attached – see image). • Optical microscopy conducted • Polished block analysis: Metallic iron in form of wüstite; mostly corroded. Fayalite slag matrix. • Summary comments: “Crown material”. Lump of crown mate- rial from bloomery smelting. FIGURE I.5 Archaeometallurgy sample 010 Ek-A 96..