Photographs by
JEFFREY SCOVIL
Fifth Edition
Sponsored by the National Audubon Society,
the National Wildlife Federation, and
the Roger Tory Peterson Institute
THE PETERSON FIELD GUIDE SERIES®
Text and illustrations copyright © 1953, 1955, 1960, 1976, 1996 and © renewed 1981, 1983, 1988 by Frederick H.Pough
ABOUT THIS BOOK
The compilation of a pocket Field Guide to mineral identification that is both comprehensive enough for the seriouscollector and basic enough for the beginner involves choices of what to include and what to omit; no selection canplease everyone. More than 3,500 different minerals have been described to date, with annual additions. Yet 97 or 98 percent of the total number of different minerals of the earth's rocks are made up of less than a dozen species, with two, quartz and feldspar, coming in at about 90 percent. All the important minerals are described here, as well as a selection of rare and more intriguing ones that collectors may not encounter outdoors, but which, when they do, will be far more thrilling than the usual find.
In preparing this guide an attempt has been made to simplify the identification of minerals and give as much
information as possible to help the beginner form the habit of observing and testing. A certain minimum of mental application and special equipment is prerequisite, as for other nature-study hobbies. A hammer, a lens, some testing equipment, and a few chemicals are as essential to the serious study of minerals as a pair of field glasses is to the birder.
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On the other hand, the book is not intended to be a textbook of mineralogy. A Field Guide aimed primarily at identification is not the place for a complete course in crystallography or the details of analytical chemistry. This is a practical book, with as much firsthand observational information as possible in a limited space.
Identification Tests: This guide departs from descriptions of tests, procedures, and physical properties used in other books. The tra-ditional tests given here have been repeated and observed by the writer, and many interesting observations are included that have been forgotten in the century since blowpipe and chemical testing was our primary recourse. This aspect has been retained and the presently customary electron microscope and x-ray structural methods of testing omitted because the latter are unsuited to the training and accessible facilities of the average amateur, and their inclusion can only have a discouraging effect on the beginner. The significant minerals of today hardly differ from the significant minerals of Pliny, Agricola, and Goethe. New emphasis has been placed on the use of the ultraviolet light. Now a relatively common piece of equipment for the pursuit of mineralogy, it provides an extremely rapid means of distinguishing between some otherwise similar species. Used in this way, ultraviolet light becomes an essential addition to the collector's equipment. The use of a solution of cobalt nitrate is also emphasized in this Field Guide, for when we have to distinguish between only two minerals by some special type of behavior, as we do in this book, slight differences in reaction are immediately apparent.
The failure of today's professionals to think in terms of traditional testing, together with a lack of initiative among the amateurs, has reduced home testing and identification of minerals to its present secondary status. Some suggestions for new tests will be found in the testing section of the mineral descriptions; they are particularly appropriate to a book in which no attempt is made to distinguish by blowpipe tests one mineral from 3,499 others.
Here, on the contrary, the problem has been reduced, eliminating most similar compounds, with the aid of common sense to eliminate all dissimilar compoundsto the determination of which one of two or three similar species is in question.
Illustrations: For this edition the plates are grouped at the center of the book and stem from multiple sources. An attempt has been made in the main to select specimens typical of those that might be found by the amateur and to illustrate to the best possible advantage the characteristic appearance, size, and associations of each mineral. The crystal drawings on the legend pages opposite the plates usually show two different crystal habits: the left-hand, or top drawing when they are vertically arranged, is the more common one; the right-hand (or lower) is a less frequent but still important habit. Occasionally there is a sketch to emphasize a manner of growth. Measurements: Metric equivalents are given to supplement the traditional U.S. inches and feet. However, minerals are not limited to exact dimensions, so they do not require the same statistics important in the identifying of living organisms that mature to standard sizes. All measurements are approximations: translating 1 in. into 2.54 cm, the exact equivalent, would imply a precision that is unintended and misleading. So the policy in this book is to say 12 in. (2.55 cm) for average conditions; or, when the tendency in the crystals is on the large size, to convert it to 36 cm, or, if on the smaller size as an average, to 13 cm. The purpose of all dimensions mentioned is only to give an order of magnitude. Some minerals normally form only minute crystals, others have crystals in the 16 in. (215 cm) range, and some crystals may be enormous and measurable in yards (meters). As a rule, the rarest minerals (rare because the combination of conditions for their formation is seldom present, with a consequent infrequency of occurrence) tend to form smaller crystals. Common minerals (common because they can form under a wide range of conditions)
are more likely to be large. Often collectors are interested in obtaining the largest crystals possible; such crystals frequently come from one exceptional locality.
For Field Guide purposes it has been helpful to indicate the normal dimensions. Reference to the average sizes given will also assist the show-specimen collector in realizing just how notable a particular specimen is at least in respect to the size of the crystals. Along the inside edge of the back cover of the book is a longer conversion rule than the one given here
JEFFREY SCOVIL
Fifth Edition
Sponsored by the National Audubon Society,
the National Wildlife Federation, and
the Roger Tory Peterson Institute
THE PETERSON FIELD GUIDE SERIES®
Text and illustrations copyright © 1953, 1955, 1960, 1976, 1996 and © renewed 1981, 1983, 1988 by Frederick H.Pough
ABOUT THIS BOOK
The compilation of a pocket Field Guide to mineral identification that is both comprehensive enough for the seriouscollector and basic enough for the beginner involves choices of what to include and what to omit; no selection canplease everyone. More than 3,500 different minerals have been described to date, with annual additions. Yet 97 or 98 percent of the total number of different minerals of the earth's rocks are made up of less than a dozen species, with two, quartz and feldspar, coming in at about 90 percent. All the important minerals are described here, as well as a selection of rare and more intriguing ones that collectors may not encounter outdoors, but which, when they do, will be far more thrilling than the usual find.
In preparing this guide an attempt has been made to simplify the identification of minerals and give as much
information as possible to help the beginner form the habit of observing and testing. A certain minimum of mental application and special equipment is prerequisite, as for other nature-study hobbies. A hammer, a lens, some testing equipment, and a few chemicals are as essential to the serious study of minerals as a pair of field glasses is to the birder.
On the other hand, the book is not intended to be a textbook of mineralogy. A Field Guide aimed primarily at identification is not the place for a complete course in crystallography or the details of analytical chemistry. This is a practical book, with as much firsthand observational information as possible in a limited space.
Identification Tests: This guide departs from descriptions of tests, procedures, and physical properties used in other books. The tra-ditional tests given here have been repeated and observed by the writer, and many interesting observations are included that have been forgotten in the century since blowpipe and chemical testing was our primary recourse. This aspect has been retained and the presently customary electron microscope and x-ray structural methods of testing omitted because the latter are unsuited to the training and accessible facilities of the average amateur, and their inclusion can only have a discouraging effect on the beginner. The significant minerals of today hardly differ from the significant minerals of Pliny, Agricola, and Goethe. New emphasis has been placed on the use of the ultraviolet light. Now a relatively common piece of equipment for the pursuit of mineralogy, it provides an extremely rapid means of distinguishing between some otherwise similar species. Used in this way, ultraviolet light becomes an essential addition to the collector's equipment. The use of a solution of cobalt nitrate is also emphasized in this Field Guide, for when we have to distinguish between only two minerals by some special type of behavior, as we do in this book, slight differences in reaction are immediately apparent.
The failure of today's professionals to think in terms of traditional testing, together with a lack of initiative among the amateurs, has reduced home testing and identification of minerals to its present secondary status. Some suggestions for new tests will be found in the testing section of the mineral descriptions; they are particularly appropriate to a book in which no attempt is made to distinguish by blowpipe tests one mineral from 3,499 others.
Here, on the contrary, the problem has been reduced, eliminating most similar compounds, with the aid of common sense to eliminate all dissimilar compoundsto the determination of which one of two or three similar species is in question.
Illustrations: For this edition the plates are grouped at the center of the book and stem from multiple sources. An attempt has been made in the main to select specimens typical of those that might be found by the amateur and to illustrate to the best possible advantage the characteristic appearance, size, and associations of each mineral. The crystal drawings on the legend pages opposite the plates usually show two different crystal habits: the left-hand, or top drawing when they are vertically arranged, is the more common one; the right-hand (or lower) is a less frequent but still important habit. Occasionally there is a sketch to emphasize a manner of growth. Measurements: Metric equivalents are given to supplement the traditional U.S. inches and feet. However, minerals are not limited to exact dimensions, so they do not require the same statistics important in the identifying of living organisms that mature to standard sizes. All measurements are approximations: translating 1 in. into 2.54 cm, the exact equivalent, would imply a precision that is unintended and misleading. So the policy in this book is to say 12 in. (2.55 cm) for average conditions; or, when the tendency in the crystals is on the large size, to convert it to 36 cm, or, if on the smaller size as an average, to 13 cm. The purpose of all dimensions mentioned is only to give an order of magnitude. Some minerals normally form only minute crystals, others have crystals in the 16 in. (215 cm) range, and some crystals may be enormous and measurable in yards (meters). As a rule, the rarest minerals (rare because the combination of conditions for their formation is seldom present, with a consequent infrequency of occurrence) tend to form smaller crystals. Common minerals (common because they can form under a wide range of conditions)
are more likely to be large. Often collectors are interested in obtaining the largest crystals possible; such crystals frequently come from one exceptional locality.
For Field Guide purposes it has been helpful to indicate the normal dimensions. Reference to the average sizes given will also assist the show-specimen collector in realizing just how notable a particular specimen is at least in respect to the size of the crystals. Along the inside edge of the back cover of the book is a longer conversion rule than the one given here
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