Note on Rock Crystal See also my webpage on: Rock Crystal Trade.
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Taken from: http://archeologiemayotte.over-blog.com/pages/Dembeni-8810071.html
http://www.archaeological.org/fieldwork/afob/14471
In the following books rock crystal from East Africa is mentioned:
-Al-Biruni: The Book most Comprehensive in Knowledge on Precious Stones.
-Nasir-I Khusraw: Safar-nama
-Ibn Al-Akfani; Nukhab Al-Thakhair fi Ahwaal Al-Jawahir (Special Treasures on Characteristics of Gemstones)
-Lapidario del rey Alfonso X el Sabio; (Lapidary of King Alfonso X the Wise)
In 2013 the first archeological evidence was found:
African Rock Crystal: Production and Trade between the 9th-12th centuries
Stéphane Pradines (Associate Professor, Aga Khan University)
In August 2013, an archaeological excavation in Mayotte (site at Dembeni), a small island of the Comoros archipelago in the Western Indian Ocean, has uncovered large quantities of fragments of rock crystal in the form of chips and flakes of different sizes. With this it is now possible to be more precise than the Arab written sources on trade in the Indian Ocean during the medieval period and to pinpoint the exact international trade route and exportation centers. The quantities of rock crystal uncovered during the excavation leads us to believe that the mineral was imported to Mayotte from Madagascar in draft form, then resized and exported to the Middle East - mainly Iran and Egypt.
This rock crystal arrived in the capital cities of Baghdad and Cairo via Persian merchants who travelled with Omani boats and sailors. They travelled for months to East Africa and they were stationed in many Swahili ports like Mombasa, Zanzibar and Kilwa. Then they pushed further south towards the coast of Mozambique in order to get gold, or to the southeast to reach the Comoros. On arrival on the island of Mayotte, the merchants exchanged ceramics and other items for the precious rock crystal, which only the best parts were retained. Between the 11th and 12th century, the rock crystal was discharged in Aden, Yemen. Archives of Jewish merchants and Persian travelers tell us that the products were then transshipped and forwarded to the Egyptian ports of Aydhab and Quseir on the Red Sea. These valuable goods were then loaded to the Nile Valley and transferred by felucca to Cairo and Alexandria, the rock crystal was then shaped by skilled craftsmen.
Piece of Rock Crystal found at Dembeni.