PAPYRUS
Papyrus was used from 3000bc to about 300ad. It was replaced over time by parchment. By about 600ad it was all but gone unless no other material was available. By 1000ad it was considered an exotic material. (Paraphrased from the Catalog of Illuminated Manuscripts, British Library)
"The Egyptian brush-pen was made from a thirsty, thin-stemmed rush plant (Juncus maritimus) usually cut to a length of around 9 inches. ... The ink used by the Egyptian scribes was so stable that it has retained its dense black color after thousands of years. It was made of carbon, usually fine soot, mixed with a binding agent such as gum."
*The Story of Writing by Donald Jackson