Examples of Some Relevant Books

garnets

Dana, Edward; and Ford, William
Textbook of Mineralogy
Wiley, USA, 2011

Klein, Cornelius; and Philpotts, Anthony
Earth Materials - Introduction to Mineralogy and Petrology
Cambridge University Press - New York, 2013

Lauf, Robert J -- (For example, many more sister volumes)
Collector's Guide to the Garnet Group
Schiffer Publishing - Atglen PA, USA, 2012

Lauf, Robert J
Collector's Guide to the Tourmaline Group
Schiffer Publishing - Atglen PA, USA, 2011