Silk fragment with green dye
Plain weave in silk
Length 14.2 cm x Width 7.3 cm
Museum no. LOAN:STEIN.550 (M.I.xii.003)
On loan from Government of India and the Archaeological Survey of India
This crumbled piece of plain woven light brown silk appears to have traces of bluish green colour on its surface. However, after examination under a microscope, in addition to blue fibres, some yellow incrustations could be seen. Small blue and black particles were also observed. The blue fibres were dyed with indigo, the yellow pigment was found to be the arsenic-containing compound pararealgar, As4S4, and the blue particles were made of lapis lazuli. The black particles were made of carbon black. Lapis lazuli is a rock, not a mineral, and can be made into jewellery, boxes and ornaments it was also ground and processed to make the pigment ultramarine for paint. The mines in northern Afghanistan have produced lapis lazuli for export for several thousands of years, but it could also be found in the mountains of the Kingdom of Khotan.