Actually, black chevrons are rare, I have never seen black chevrons with 7 layers. So in the 17th century we never, it seems to me, made of black chevrons. Then there are black chevrons like the ones you photographed. But I also have bigger black chevrons found on the African markets. Here is the picture of this chevron with 5 layers.
It measures 30,5mm in length and 21mm in diameter.
You can see other pictures on my site: KIKASBEAD on Etsy.com