ii

The Mineral Grain

and Mineral-grain

Surfaces:

a low-technology

approach, description,

and use

By Wallace D. Kleck NoticeI claim copyright protections for this work and its contents. However, I freely

grant anyone permission to make one paper or electronic copy for their own personal use. If any

of the contents are quoted, there must be an appropriate technical reference. The total or any part

of this work, may not be copied for sale or sold without the direct, personal permission of

Wallace D. Kleck or his estate. I may be contacted by standard-mail at 23940 Basin Harbor Court, Tehachapi, CA, 93561 or by e-mail at wkleck@sbcglobal.net.

So stated, May, 10, 2012, Tehachapi, California.

mailto:wkleck@sbcglobal.net

iii

TABLE OF CONTENTS

Note, page numbers are shown for 1st and 2

nd

level headings

------section heading---------------------------------------------------------------------page

ABSTRACT 1

INTRODUCTION 1

DEFINITIONS 2

FORMATION OF GRAINS 4

GRAIN SURFACESPROCESSES OF FORMATION 5

Grain Growth 5

Growth-free

Growth-partially-free

Growth-restricted

Dissolution (s.l.--sensu lato) 6

Mechanical Modification 6

Other (Grains at or Near Equilibrium) 6

MINERAL GRAIN AND CRYSTAL 7

MINERALOID 8

GRAIN SURFACESDETAILS 8

Growth Surfaces (redefined; new) 9

Type-1 surfaces

Type-2 surfaces

Type-3 surfaces

Type-4 surfaces

Type 4-1 surfaces; mutual growth and relative bond strength

Type 4-1 surfaces; metamorphic environments

Type 4-1 surfaces; igneous environments

Type-5 surfaces

Paramorphic-surfaces (redefined) 22

Dissolution (s.l.) (modified) 23

Features of melt surfaces

Features of a chemical solution surface

Features of dissolution surfaces on quartz phenocrysts in rhyolite

Recognizing dissolution surfaces

Mechanically modified (new) 28

Phantom Surface (modified) 30

Artificial 30

Mineraloid (modified) 30

Gel-mineral (modified)

Grain-replaced (new)

Crystallized gel (new)

Grain-metamict.

Grain-domain Containing (new)

THREE EXAMPLES 34

Pegmatite-Example 1 34

Quartz in Rhyolite (Crystal Tuff)-Example 2 35

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Spodumene Crystal-Example 3 36

DISCUSSION 36

Other Surfaces 36

Crystals 37

Mixed and Complex Surfaces 37

Surfaces on Grains from Pegmatite Rocks 37

Grains in Cavities36

Some Comments on the Nature of Selected Minerals 42

Feldspar (in crystal tuffs)

-quartz (in crystal tuffs)

Mica (in a variety of environments)

Graphite (in tactite)

CREATION OF SUITABLE GRAINS FOR STUDY 43

Weathering 43

Cavities 44

Artificially Crushed, Broken, or Naturally Fragmented Rocks 44

Separation by Chemical or Physical Properties 44

ACKNOWLEDGEMENTS 44

REFERENCES CITED 45

1

The Mineral Grain and Mineral-grain Surfaces: a low-technology approach and uses

Wallace D. Kleck wkleck@sbcglobal.net

23940 Basin Harbor Court, Tehachapi, California 93561, USA; retired--no present college

affiliation

ABSTRACT

A grain (mineral grain) is redefined as the fundamental unit of mineralogy. Grain surfaces (in

3-dimensions) provide considerably more information about the geologic history of grains in a

rock than do a small number of thin sections through grains. Grain surfaces are formed by one or

a combination of growth, dissolution, and mechanical modification. Herein, grain surfaces are

divided into six classes and ten subclasses (in parentheses)growth (type-1, type-2, type-3,

type-4, type 4-1, type-5), paramorphic, dissolution, mechanically modified (cleavage, parting,

fracture, smoothed), phantom, and artificial. In addition, mineraloid is redefined and divided into

five subclasses (gel-mineral, grain-replaced, crystallized gel, grain-metamict, and grain-domain

containing).

Type 4-1 growth surfaces are a newly defined type of surface, resulting from competitive growth

(primarily) in igneous and metamorphic environments. It is proposed that the determining factor

in the goodness of development of crystal surfaces on such grains is the relative difference in

bond strength. An imprecise measure of the difference in bond strength is the relative difference

in mineral hardness (H). Where the difference of hardness between two competing grains is

approximately >2, recognizable crystal surfaces develop.

INTRODUCTION

For approximately 100 years, petrologists and mineralogists have dealt with the interpretation of

the features of mineral grains primarily in section. This is a useful and well developed technique,

but it ignores features that can provide a great deal of information about the environment of

formation of mineral grainsi.e. the nature of and the features on the surfaces of the mineral

grains. These surface features are the last to form and then are the latest of the mineral-grain

surface features. For a compete interpretation of the grains, this information needs to be added to

information about the internal (and former grain surfaces) features gained by section studies.

This paper has three purposes:

To gather and develop information on the origin and nature of grain surfaces;

2

To develop a classification system that places this information in a coordinated and logical format;

To demonstrate how this information can be used. In doing this, it is necessary to develop a certain amount of new terminology and to modify some

existing terminology; if this approach is valid, the new and modified terminology will need to

become a part of mineralogy and petrology. It is suggested that information on grain surfaces

become one of the standard types of information collected and interpreted for mineral grains in

rocks.

Further, this paper is primarily concerned with natural, solid grains that have formed at or near

the surface of Earth. It is not that other substances or environments are uncommon or

uninteresting, but for the practical reasons of length and coherence of topic. The surface and near

surface processes of the planetary body called Earth are complex enough. But as we scientists

begin to consider the interior of Earth, outer-space, other planetary bodies, etc., the job of

understanding natural solids grows to unimagined proportions. Truly, we are cursed (or blessed)

and live in interesting times.

Note that Geosphere (the GSA online jo