Interesting muscovite specimens from Pakistan: epitaxial incrustation and pseudomorphism after beryl. Published in the Journal of the Gemmological Association of Hong Kong (2010).
Author(s): M.S. Krzemnicki
Asterism in beryl, aquamarine and emerald- an update. Published in Journal of Gemmology, 2004.
Author(s): K. Schmetzer, L. Kiefert, H.A. Haenni
Blue-green emerald from Nigeria (a consideration of terminology). Published in Australian Gemmologist, 1992.
Author(s): H.A. Haenni