Quartz family minerals, a handbook for the mineral collector by Henry Carl Dake 1938 Producer's Note DEDICATED to all those anonymous writers of the past who have preserved mineral information of great value to the present generation Mineralogists Preface With the manyfold increase during the past decade in the number of persons seriously interested in one phase or another of the mineralogical sciences, there has arisen a growing demand for one compact volume on the subject of quartz, where the most essential information w^ould be made available for reference to the amateur and the professional student alike. In culling the widely scattered Hterature upon the subject, the authors were overwhelmed with its profusion. They dared not even brief the greater bulk of it. They were reminded of Buckles's statement in his ''History of Civilization in England": "We live in that predicament that our facts have outstripped our knowledge and now encumber its march." Early realizing the futility of attempting a complete treatment of a mineral so diversified and abundant, they have set themselves to the task of producing a volume which will answer many of the more common, general, and perplexing questions about quartz minerals, yet give such perspective to the subject as will encourage the reader to set out on a Hne of further research and investigation for himself. All books should be written with certain fixed limitations and objectives in mind. The authors adopted these: 1. They have tried to give the reader definite information concerning the typical, rather than the exceptional, examples. They are not interested particularly in freaks or curiosities of the quartz world, unless these emphasize some definite point or give a clue to the solution of some obscure or puzzling observation. 2. In general, they have attempted to allot space in proportion to the importance of the variety under consideration, though this, again, may be largely a matter of opinion. It will be Preface immediately apparent that the varieties (subspecies) of quartz; are not all of like importance; therefore, an equal amount of space should not be devoted to each. Some lesser varieties, however, have been treated at greater length, because of unique features or some historical or economic value attached to them. 3. They have endeavored to render some distinct contribution to the literature of the field by listing many of the known contemporary American localities of interest to collectors—■ especially those of the western or newer sections of the country, which have been recently explored and remain comparatively unknown. At the same time, attention has been given to some of the less known of the older localities which are yet available and accessible to present day collectors. 4. They have attempted to check from original sources as many as possible of the statements that are made. This proved most difficult, and the authors are indebted to many persons for assistance. The readers may judge to what extent these aims have been achieved. The authors have realized their inability to cover the whole field of important localities throughout the entire world, many of which are now exhausted, and many more of which are as inaccessible to the average collector, striving to make a modest collection of minerals for his own edification and pleasure, as though they were located on the planet Mars. To catalogue geographically a mineral as widespread and common as quartz would require a fairly complete gazetteer of the earth, which plainly is quite beyond the scope of this volume. The central idea of the book is helpfulness. The intention is to help, more than anybody else, the fellow who is struggling along by himself, who knows minerals, appreciates their beauty, and understands that they can tell him something. If it is pos' sible here to teach him the proper slant, or give him the clue to the correct interpretation of the meaning of minerals and the important part they play in the economy of things in nature, the authors will be amply repaid for their efforts. Preface To acknowledge indebtedness to even^ individual who has helped make this work a reality would be as impossible as to tell the whole story of quartz complete in ever)'' detail. The authors have dra^^Ti freely upon the general literature. Inferences have also been made from certain artifacts antedating recorded histor^^ Some admirable obser\^ations which have found their way into print have been made anonymously, and so in many cases it is impossible to give credit. The books and texts on minerals which have been consulted in the preparation of the book are listed in the Selected References at the close of the book. Many friends have generously lent a helping hand by answering numerous inquiries to the best of their ability, and thanks is hereby extended to all who have so assisted. The authors are especially grateful for special information and advice given by Dr. Esper S. Larsen, Har\^rd University; Dr. John R. Ball, Northwestern University; John Melhase, Berkeley, California; E. Mitchell Gunnell, University of Missouri; J. Lewis Renton, Portland, Oregon; George J. Huss, Marquette Mineral Society, Chicago; Edward Wigglesworth, Boston Society of Natural History; WilHam Pitts, Sunny \^le, California; D. H. Newland, New York State Museum; Prof. George Beck, Washington State Normal College; Raymond C. Moore, University of Kansas; Dr. W. H. Over, South Dakota State Museum; Prof. Francis T. Jones, Pacific University; and George L. English, Gus Brockmann, and Harlow D. Grose for photographic contributions. They are also immeasurably indebted to the files of the following mineral magazines which have made important contributions to the Hterature: Minerals, edited by W. M. Goldthwaite (discontinued); Mineral Collector, edited by Arthur Chamberlain (discontinued); The American hiineralo^ gist, edited by Walter F. Hunt; The Mineralogist, edited by H. C. Dake; Roc^5 and Minerals, edited by Peter Zodac; and Sands, Clays and Minerals (British), edited by A. L. Curtis. It might be of interest to some to know the parts of the book for which the joint authors were indixidually responsible. This Preface would be hard to state precisely, for each has assisted the others. In a general way, Mr. Wilson was responsible for the early chapters of the book, up to and including the discussion of the crystalline forms; Mr. Fleener's voluminous notes, the product of a Hfetime of reading and research, fitted him preeminently to prepare the chapters on the numerous varieties and subvarieties of amorphous quartz, including the part on opal; Mr. Dake's many years of experience as editor of The Mineralogist and his wide travels in the West have given him a valuable fund of information on the subject of agates, chalcedony, and petrified woods, and these chapters were arranged by him. The authors realize the inadequacy of certain phases of the work and regret that lack of space has forbidden the pursuit of some of the Hnes of discussion to their full conclusion. It goes without saying that they would appreciate correspondence or criticism concerning any statements which might appear to be debatable, and they will also be pleased to answ^er any questions that may help to straighten out problems which seem troublesome to any reader. H. C. Dake, Frank L. Fleener, Ben Hur Wilson. Xll Contents Chapter X Agate — Chalcedony 157 Chapter XI Geodes and Thunder Eggs 206 Chapter XII Unusual Quartz Types 225 Chapter XlII The Opal 239 Chapter XIV SiLICIFICATION AND PeTRIFIED FoRESTS 255 Chapter XV The Art of Cutting Quartz Gems 276 Index 297 Section of Polished Agate (Frontispiece) iv Axhead Fashioned from Agate 14 Representative Minerals of the Quartz Family 20 Quartz Crystal, Showing Striations 70 Twin Quartz Crystal—Kai, Japan 75 Quartz Crystals—Hot Springs, Arkansas 80 Quartz, Variety Amethyst 88 Sagenitic Quartz Cr>'stals 98 Flexible Sandstone 118 Siliceous Sand Crystals 119 Arrowheads of Common Opal and Agate 126 Display of Quartz Minerals 130 Jasper—Variety Orbicular (Egyptian) 133 Jasper—Carved Paper Knife 140 Jasper—Variety Orbicular 146 Rimrocks of Oregon 158 Cavity Lined with Drusy Quartz l6l Nodular Growth 164 Banded Agate 166 Fortification Agate 170 Cabochon-style Cut Agates 175 Moss Agates 179 Tree Cast in Lava 183 XV Breccia Agate 189 Sagenite Agate 193 Moss and Sagenite Agate 195 Moss Agate—Cut Gems 197 Polka-dot "Agate" 200 Banded Agate 201 Fortification Agate 204 Quartz, Crystal-lined Geode 207 '"Cinderella's Slipper" 213 Agate-filled Nodules 215 Nodule—Exterior and Interior 218 Nodule—-Moss-agate Type 220 Agate- and Opal-filled Nodule 222 Agate-filled Nodule 224 Coral Petrified by Chalcedony 229 Phantom-quartz Crystal 236 Etched-quartz Crystal 238 Opalized Wood—Polished 250 Lx)g of Jasperized Wood 256 Petrified Wood—Tree Section 262 Jasperized Wood 265 Polished Ribbon, Banded, Moss, and Iris Agates 278 Sawing Agates 279 Grinding Agate to Shape 281 Sanding Operation 282 Hard Felt Polishing Buffs 283 Facet-cutting Gem Stones 286 Home Gem-cutting Shop 288 Modern Gem-cutting Laboratory 291 xvi QUARTZ FAMILY MINERALS 3 CHAPTER I \S/hy Know Si^i^tz We hear, today, much emphasis and stress being placed upon the value of a well- rounded, general education. In fact, practically our entire educational system, up to and in many instances including our liberal arts colleges, builds the curriculum on the basis of giving the student broad knowledge intended to integrate him thoroughly with his natural surroundings. Therefore, any person with a balanced