American Mineralogist
REGULAR ARTICLE
135 Prospect of mineralogy
142 The frequency of twin types in quartz crystals
163 The unit cell and space group of lindgrenite
173 Some comments on the Buerger precession method for the determination of unit cell constants and space groups
181 Crystallography of spangolite
188 Retgersite, NiSO4 – 6H2O, a new mineral
195 Thermal study of rhodochrosite
220 What is a mineral?
226 A definition of Euclidean geometrical symmetry
229 Supplementary note on the Aggie Creek meteorite
229 The Aggie Creek meteorite from Seward Peninsula, Alaska
238 Acceptance of the Roebling Medal of the Mineralogical Society of America
288 Conference on the teaching of crystallography
293 Correspondents, fellows, members and subscribers of the Mineralogical Society of America
335 A new locality for ludlamite
340 Announcement of the thirtieth Annual Meeting of the Mineralogical Society of America; Nominations of Officers for 1950
AWARD
234 Presentation of the Roebling Medal of the Mineralogical Society of America to William Lawrence Bragg
NEW MINERAL NAMES and DISCREDITED MINERALS
339 New mineral names; New Data; Discredited minerals
NOTES and NEWS
331 Notes and news: Pseudotachylite of the Antietam quartzite
PROCEEDINGS
267 List of former officers and meeting places
267 Proceedings of the twenty-ninth annual meeting of the Mineralogical Society of America at New York, N. Y.
337 Proceedings of Societies
MEMORIAL
242 Memorial of Alfred Lacroix
249 Memorial of Alfred Church Lane
253 Memorial of James Greenfield Manchester
256 Memorial of Lewis Gardner Westgate
261 Memorial of Herbert Percy Whitlock
TABLE OF CONTENTS
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SPECIAL COLLECTIONS
Table of Contents
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Special Collections
American Mineralogist is an international journal that publishes mineralogical papers of broad interest to the geoscience and materials science community.