Chemical Composition: EMP analysis from sample, Bronze:
Cu, 93.71; Sn, 4.12; Pb, 0.02; Zn, 0.00; Fe, 0.13; Ni, 0.31; Ag, 0.01; Sb, 0.01; As, 0.39
T. Richardson, June 1999
Chemical Composition: ICP-MS/AAA data from sample, Bronze:
Cu, 94.56; Sn, 4.42; Pb, less than 0.025; Zn, 0.003; Fe, 0.18; Ni, 0.32; Ag, 0.02; Sb, 0.02; As, 0.46; Bi, less than 0.025; Co, 0.021; Au, less than 0.01; Cd, less than 0.001
J. Riederer
Technical Observations: The patina is dark green and red. The dagger is a solid lost-wax cast. Minor casting flaws are visible on the blade edges and on the hilt.
The hilt and blade were cast in one piece. There are long striations or tool marks along the length of the hilt and marks or impressions at the curved edge of the hilt. The striations do not mark the rivet holes, which indicates that the holes were made in the metal after the surface was filed. There are no visible tool marks on the sides of the hilt, but there is preserved organic material from chance association on each side. The heights of the sides are uneven. There are also tool marks on the hilt of the dagger. Soft oval impressions (c. 2.0 mm x 0.5 mm) were made on the flat inlay surface of the hilt using a tool with a rounded edge. This may have been done not only to smooth out the surface of the wax, but also to shape it.
There are striations across the blade near the hilt, and others are found along the length of the blade with layers of corrosion under them. There are pseudomorphs of an organic woven material on the blade. The material has a warp and weft with approximately three threads per millimeter. The threads are c. 0.1 mm wide, and there is no evidence of a twist, but they cannot be identified due to their mineralization. The woven material may have been the interior lining of a scabbard or simply a cloth wrapped around the blade, but no published evidence of pseudomorphs on Luristan bronzes could be found to compare with this piece.
A sample (4 mm x 8 mm) was cut 3 cm from the tip of the blade, in an area free of tool marks and of pseudomorphs, for metallographic analysis. The section was mounted in epoxy resin, polished, and etched with potassium dichromate followed by ferric chloride. The section was examined under a polarizing microscope both before and after etching. Inclusions in the metal are visible as bluish-gray spots. They vary in shape across the section. Along the midrib of the blade, they are round, whereas on the cutting edge they are elongated. This elongation of the inclusions was caused by cold working or hammering the blade to harden the metal. Since the inclusions are elongated at the blade’s edge, as opposed to the midrib, the hammering must have been concentrated at the edge. Annealing twins and deformation lines are also visible. The cutting edge of the blade has a higher density of deformation lines than the midrib, which has some grains with no deformation lines at all. The higher density of deformation lines and the elongated inclusions support the conclusion that this dagger was cold worked and annealed, possibly more than once, with a final stage of cold working that focused primarily on the blade’s edges.
Tracy Richardson (submitted 1999)
