Chapter III: Organic Rocks (dark Colored)

A. Soft; spongy when wet; very lightweight when dry; forms in swampy
places
1) Fine mass with coarse plant fragments; dark gray to black
Peat (13)
2) Plant fragments small and not easily recognized; fine-grained;
black to dark gray; earthy
Muck
B. Hard but can be scratched with a knife
1) Black; contains bands of shiny and dull material; burns well
Coal (14)
2) Dark gray to black; does not contain shiny bands; splits into
thin sheets; burns poorly or not at all
Bituminous shale

EQUIPMENT FOR COLLECTING

1. Hammer (bricklayer’s) with one chisel or pick head.

2. Cold chisel about 6 inches long with an edge about ½-inch wide.

3. Dilute hydrochloric (muriatic) acid (10 percent solution) in a
dropper bottle for testing the presence of carbonate minerals.
Mark the bottle POISON. If acid is spilled on skin or clothing,
wipe immediately and, if possible, rinse with water.

4. Magnifying glass or hand lens—10 power is probably most useful.

5. Hardness testers—penny, square of window glass, pocket knife, or
nail.

6. Streak plate—piece of unglazed white porcelain (such as the back of a
tile) for testing the color of the streak of minerals.

7. Notebook and pencil for keeping records of the locality and bed from
which specimens are collected.

8. Collecting bag—a musette bag, a knapsack, or similar bag of strong
material.

9. Heavy gloves and goggles to protect hands and eyes.

10. Labels and wrappings. Field identification of specimens may be
written on adhesive tape and attached to the specimen or on a slip
of paper enclosed in the wrapping. Newspaper, brown paper, or
paper bags can be used for wrapping specimens. Label the outside
of the wrapped specimen too. Take only the best specimens home
with you. Trim specimens to hand size (about 2 by 3 inches).

All specimens should be labeled with the following information: name of
mineral or rock type, where found, collector’s name, and date. As
your collection grows, you may want to set up a system of
cataloging. List specimens and assign a number to each one. Place
a small amount of white enamel on a corner of each specimen; when
the enamel dries, number the sample with India ink; coat number
with lacquer. Corresponding numbers should be entered on your list
of specimens.

EDUCATIONAL EXTENSION PROGRAM

This book was prepared by the Educational Extension Section of the Illinois State Geological Survey, principally Betty Jean Hanagan, I. Edgar Odom, and Shirley J. Trueblood, under the direction of George M. Wilson. They were assisted by other members of the Survey staff, especially J. E. Lamar and J. C. Bradbury of the Industrial Minerals Section.

Educational Extension also serves the public by assembling and distributing rock and mineral collections for Illinois educational groups, giving lectures, preparing exhibits, answering queries about identification of rocks and minerals, reporting Survey news, and conducting earth science field trips.

During each year six field trips are conducted in widely separated parts of the state for teachers, students, and laymen. The general program is especially designed to assist in teaching the earth sciences and to help make Illinois citizens aware of the state’s great mineral wealth.

Illinois State Geological Survey
Urbana, Illinois

Transcriber’s Notes

—Silently corrected a few typos.

—Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.

—In the text versions only, text in italics is delimited by
_underscores_.