May I recommend the following publications: Hawthorne, F.C., Oberti, R., Harlow, G.E., Maresch, W.V., Martin, R.F., Schumacher, J.C., Welch, M.D. (2012) Nomenclature of the amphibole supergroup. American Mineralogist: 97: 2031-2048. Hawthorne, F.C. (2016): Short-range atomic arrangements in minerals. I: The minerals of the amphibole, tourmaline and pyroxene supergroups. Eur. J. Mineral. 28, 513-536. Furthermore, please see: "Fleischer's Glossary of Mineral Species, Twelfth Edition 2018" by Malcom E. Back, The Mineralogical Record Inc., Tucson. Here you will find the latest updates relating to the Amphibole Supergroup. Best regards, Guenter Grundmann

Guenter Grundmann , thany you very much.

Mineral chemistry alone is not going to be able to tell you whether your amphibole is of primary magmatic or metamorphic in origin. Many amphiboles are stable over a wide range of temperature and pressure conditions, and a single species may have either a magmatic or metamorphic origin. You need to make some thin sections and examine your samples under a microscope. Examine the textures and relationships between the amphiboles and the other minerals in the sample. Look at the regional structural information from where your specimens came from. All this ground work needs to be done before you dive into putting your amphiboles under an electron beam!

I agree with Jeremy Preston. Chemistry alone is not enough. Structure of the area, metamorphic condition of the surrounding rocks of the outcrop under study are important. Perhaps more importantly, good study of the thin sections and textural relations of the amphibole(s) with the adjacent minerals. Despite all these studies and EPMA studies, one may still not find the correct answer. For example, if the metamorphism is not intense and is static, i.e., not accompanied by pervasive deformation, and the rocks contain relics of igneous amphibole, it may be difficult to tell whether the younger amphible is metamorphic, deuteric or formed during uplift/unroofing..

Thank you. Jeremy Preston. Thank you, M. Qasim Jan .

I think that secondary amphibole have less than 1 wt% TiO2(eg. tremolite-actinolite),while primary amphibole have more than 1 wt% TiO2(magnesiohornblende,hornblende.....) this values from chemical analyses of amphiboles.

Himy Moussa@

TiO2 does depend on conditions of formation, and composition of the rock/magma. In granulites facies, horblendic amphiboles can have a lot of TiO2

M.Qasim

My case is some rocks metamorphosed in the greeschist facies.

In some places metasomatic amphiboles can be distinguished from magmatic granite by the fact that metasomatic amphiboles develop quartz sieve textures and magmatic amphiboles do not have tiny quartz oval inclusions. However, the metasomatic amphiboles are also associated with myrmekite and magmatic amphiboles are not. Lorence

You may like to see the publication "PRIMARY MAGMATIC AMPHIBOLE IN ARCHAEAN META-PYROXENITE FROM THE CENTRAL ZONE OF THE LIMPOPO COMPLEX, SOUTH AFRICA. SOUTH AFRICAN JOURNAL OF GEOLOGY 2016 • VOLUME 119.4 PAGE 607-622 • doi:10.2113/gssajg.119.4.607.