Hi Marcus,
That clod shot incites me!
Right now that my computer man provided with a provisional email until Outlook will work again:
Please do email me that illustration and let me know whether it is the same group discussed in
Jan Piet Puype & Harm Stevens:
Arms and Armour of Knights and Landsknechts, in the Netherlandish Army Museum.
Delft, 2010. ISBN 978-90-5972-413-6, pp. 334-9.
In the book, it says 13
75, though ...
Please see top five attachments - and my thread:
http://www.vikingsword.com/vb/showth...ight=clod+shot
The two last attachments depict 15th c. stone shot consisting of quartzite and black flint; Puype/Stevens, p. 332f.
Marcus, all considered, there seems to be a high probability that your item, too, consists of quartzite.
Thanks, and best,
Michl