Lapis Amianthus

Asbestos
Linum Asbestium
Metallotheca Vaticana Opus Posthuman, 1719

Crocidolite (blue asbestos),
(Photo by Raimond Spekking) (Wikimedia)

It was rarely used, and only externally in plasters. However, it overlaps Actinolite, used in TCM.