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ABSTRACT

Building stones provide conveniently located andaccessible “urban outcrops.” As such, building stonesmay be used for semester-long student research projectsin upper-level geology courses. I present students in myEarth Materials class with a scenario: A building ownerin downtown St. Petersburg hires you as a geologicconsultant. The owner is considering replacing the stonecurrently adorning the building. Write a persuasiveessay discussing the identity, geologic history, andsuitability of the building stone in its current use.Compare and contrast the current building stone withseveral other building stones that might be used for thejob.

To gather data for their consulting reports, studentsuse a combination of standard field tests andpetrographic techniques to identify the building stonesand determine possible geologic histories. The studentslead a walking tour during the semester to report on their progress and ask for ideas from their classmates. Theproject culminates in both oral and written reports aimed at convincing their “clients” to buy the most appropriatebuilding stones. As part of this paper, a student whocompleted the project in the fall of 2000 provides a briefoverview of his research and a positive assessment of hisoverall experience.

Keywords: Education - undergraduate; education -geoscience; mineralogy andcrystallography

INTRODUCTION

Natural outcrops are often inconveniently located faraway from college campuses. In central Florida, forexample, the selection of natural rock outcrops is limitedto limestones and phosphates while the nearest outcropsof igneous and metamorphic rocks are nearly 400 milesaway in Georgia. The mixed architecture of downtownSt. Petersburg, Florida, however, includes a variety ofbuilding stones (Figure 1). To take advantage of thissituation, students in my Earth Materials course studythese building stones and create a geological walkingtour of downtown St. Petersburg.

Rather than taking part in an organized class tour,the students themselves conduct field work early in thesemester to identify locations that use building stones.During the semester, the students use field andlaboratory techniques to identify minerals and deter-mine the rock types of the building stones. Besides

constructing formal written and oral reports, the classtakes a walking tour of downtown St. Petersburg wherethe students describe what they have learned at theirchosen “outcrops.”

To simulate a formal research project, the studentsare presented with a scenario: You are an impartialgeologic consultant hired by the owner of your chosenbuilding in downtown St. Petersburg. The owner isconsidering replacing the stone currently adorning thebuilding and has hired you to draft an opinion basedsolely on the geological properties of various stones andthe current use of those stones on the building. Write apersuasive essay designed to convince the owner thatthere is a single best stone for the structure. Compare and contrast the properties of the current building stone withother common building stones. Students gatherinformation by completing a series of tasks, culminatingin both oral and written reports (Table 1).

I designed this project to be part of a sophomore- tojunior-level course entitled Earth Materials. Studentswho typically take the class are majoring in marinescience and specializing in marine geology orgeophysics. I condensed the information presented in amore traditional two-semester mineralogy and pet-rology sequence to accommodate the constraints of theone-semester Earth Materials class. The course providespractical experience with optical mineralogy techniquesas a part of the broader study of rock and mineralcompositions, properties, occurrences, and clas-sifications. I have taught the Earth Materials class fivetimes and have assigned the building stone project twice. One student has summarized his work and brieflyevaluated the project in Figure 2.

FIELD WORK

Within the first month of the semester, students mustchoose a building site. They may explore downtown St.Petersburg on their own or join a field trip during one ofour lab periods. I provide students with maps derivedfrom MapQuest.com and specify that they must choosebuildings from an approximately eight by eight blockarea in the core of downtown. The limited area simplifiesplanning for the final walking tour when the entire classvisits all of the chosen buildings.

During the initial visit, students introduce them-selves to the building owners. Most owners are en-thusiastic about the project and are happy to provideinformation. In two cases, the owners provided pieces ofthe building stones that had come loose. By the timestudents choose a building, they have studied mineralsin hand specimens and have learned basic mineralidentification techniques. If the owners are agreeable,

404 Journal of Geoscience Education, v. 50, n. 4, September, 2002, p. 404-409

BUILDING STONES AS RESOURCES FOR STUDENT RESEARCH

Laura Reiser Wetzel Department of Marine Sciences, Eckerd College, St. Petersburg, FL 33711,

[email protected]

students perform hardness and acid tests, take pictures,and complete sketches.

About two-thirds of the way into the semester, theclass visits each “outcrop” as a group during a labperiod. Each student describes his or her progress ondiscovering the identity of the building stone and asksothers in the class for their ideas (Figure 3). I ask studentsto treat their buildings as field trip stops for the classwhere they are the experts on the outcrops. Studentsshould identify individual minerals and indicate the rock type (e.g., granodiorite, quartz arenite, mica schist, etc.).By the time the class takes the walking tour, studentshave completed their studies of igneous andsedimentary rocks and have started work on meta-morphic rocks. They should, therefore, be able tocontribute to a discussion about each building stone.

LABORATORY WORK

In the first year of this project, students obtained samplesfrom building stone suppliers and cut billets that I thensent to a thin sectioning company. This process took asignificant amount of time because companies typicallyrequire at least four weeks to make thin sections. In

subsequent years, therefore, I will prepare the thinsections, occasionally creating new thin sections asstudents explore new buildings. Reusing the thinsections will save both time and money.

During one class period and on their own time,students study their building stones with the help ofpetrographic microscopes. I suggest that they completethe following tasks:

• sketch a representative view of the thin section underboth plane and polarized light

• identify all minerals• specify distinguishing characteristics of the minerals

such as twinning, crystal habit, cleavage, pleochroism, interference colors, etc.

• discuss textural features• identify the rock type (e.g., granite, basalt, siltstone,

etc.)• specify any differences between the rock they examine

in thin section and the building stone actually used indowntown St. Petersburg on their chosen building.

Wetzel - Building Stones 405

Table 1. A brief outline of the building stone project.

FINAL PRODUCTS

The students focus on producing written and oralconsulting reports aimed at their “clients,” the owners oftheir chosen buildings. I specify that they treat theirclients as intelligent business people who are interestedin the geologic context and the material properties ofthese building stones. In the written report, the studentscompare and contrast the properties of the currentbuilding stone with three common building stones. Inthe oral report, for the sake of time, they confine theircomments to the properties of the current building stone. In each report, the goal is to persuade the client that thebuilding stone is either appropriate or inappropriate forits current use.

There are four primary components of the writtenreport: (1) A detailed description of the current building

stone, including the results of the field and petrographicinvestigations (e.g., rock and mineral identification,textures, etc.). (2) A description of three other buildingstones (e.g., serpentinite, slate, oolitic limestone, etc.). (3)A comparison of the current building stone with thethree other rock types, citing advantages anddisadvantages of each when used as a building stone. (4)A conclusion recommending a particular building stonefor the client. I suggest that students include thefollowing information for all four rock types described in their essays:

• mineralogy• geologic processes that create these rock types• possible sources of the building stone (i.e., quarrying

locations)• additional uses for these rock types (e.g.,

gemstones, electronic components, road metal,etc.)

I stress that their clients are NOT geologists, so they must explain all specialized terms used in their papers.Students must explain even terms as simple as “igneous” and “carbonate.” In addition, I tell students to includethe address of the building and the current use of thestone at their chosen building site as well as anyadditional information they might find (e.g., historicalinformation, owners, uses for the building, etc.).

To assess the term paper, I employ a grading rubric(Table 2) and pay particular attention to their persuasivearguments. I emphasize that students must take aposition on the assigned topic: Which building stone dothey recommend for their client? They must supporttheir positions with evidence and cite appropriatereferences. A substantial bibliography and appropriately cited references are important parts of convincing theirclient—and their professor—that they are experts inEarth materials. I provide many building stone articlesand geologic walking tours from other cities (e.g.,Fickies, 1986; Hebrank, 1989; Withington, 1998).Hannibal and Park (1992) give a particularly detaileddescription of sources for information on buildingstones. More recently, Winkler (1997) has written Stone in Architecture: Properties, Durability , a thorough summaryof the characteristics of building stones. I also provideseveral books about downtown St. Petersburg so thatstudents can explore building histories. I leave theseresources in our laboratory so that students may usethem as they write their consulting reports.

Why focus on a persuasive perspective for the finalproducts? As consultants or as private citizens, studentsmay be asked to express their expert opinions ongeologic issues. This project is designed to improvestudents’ abilities to express their opinions in concise,confident, and informed essays. Overall, studentsenjoyed the persuasive focus of the assignment. Theyappreciated having a goal other than simply writingabout a particular topic in a standard term paper format.One student created her own fictitious firm, Eckerd


Figure 1. There are more than 20 different buildingstones used in downtown St. Petersburg, a fairlyyoung city with a population of approximately250,000 people. For example, (A) a statue carved from a fine-grained fossiliferous limestone; (B) a World WarII memorial created from a medium-grained syenite;(C) the Christ Methodist Church adorned with adecorative sandstone (D) and Keys Limestone (E). In(D) the sandstone tiles are each one to two feet indiameter and in (E) note the lens cap for scale besidethe fossilized coral.

College Geological Consultants, and provided a coverletter with an original letterhead (Figure 4). Anotherstudent chose a building with a beautiful labradoritefacade damaged in a tropical storm. Those owners wereparticularly interested in the student’s opinion regarding replacing or retaining the stone panels.

FURTHER SUGGESTIONS

An urban center of a city is only one possible place wherestudents can study building stones. College campuses,cemeteries, art museums, or historical monuments mayalso provide a diverse selection of building stones for aclass project. Although I specify that students mustchoose exterior building stones for convenient access,they could also investigate interior building stones. Toview an even greater variety of rock types, a field trip to a building stone supplier could be added.

To explore subjects beyond science, students andfaculty could collaborate with local preservation andhistorical societies. I have spoken with an archivist at theSt. Petersburg Museum of History and we are con-sidering creating a walking tour of downtown fortourists. I may also modify the written assignment so that students create documents useful to researchers at themuseum.

If an extended building stone project is too timeconsuming, consider creating a simple walking tour oflocal building stones. Several instructors have usedbuilding stones to stimulate student interest in topicsranging from mineral identification to rock weathering,

especially in introductory geology courses (e.g.,Dragovich, 1978; Kemp, 1992; Judson et al., 2000; Kvale et al., 2000; Hoskin, 2000).

CONCLUSIONS

Building stones provide an opportunity to integrateresearch into the classroom in an unusual way. By usingeasily accessible, local resources, students can experience the fundamental aspects of original and independentresearch. The semester-long project requires students toframe hypotheses as they determine the suitability ofspecific building stones, develop strategies for collectingand assessing data, form a conclusion, and presentfocused oral and written reports.

The primary disadvantage of this project is thesignificant investment of time required from bothstudents and faculty. At the very least, students requireone lab period to hold the walking tour and several classperiods to give their oral presentations. Students mayspend additional class time choosing building sites andidentifying minerals using the petrographic microscope.To prepare for the project, the instructor must acquirebuilding stone samples, find appropriate buildings in adowntown area, and conduct historical research. Thetime commitments, however, are offset by a substantialnumber of benefits beyond providing a researchexperience for students:

It enhances the college’s visibility to the public.


Table 2. The grading rubrick for the written report.


Figure 2. A brief overview and assessment of the building stone project written by a student.

It introduces students to a downtown area, providingthem with a greater familiarity with their geo-graphic surroundings.

It is an interdisciplinary exercise linking geology andhistory, providing a greater appreciation for a city’spast.

It develops students’ skills in identifying building stones, which they commonly see and can then discuss withfriends and family.

It drives home the limitations of hand specimenexamination and the power of petrographic tech-niques.

It provides a capstone experience for the class whereeach student can incorporate skills and informationlearned throughout the semester.

The time invested in the building stone project mayprevent students from learning as many details about along list of rocks and minerals as compared to thetraditional approach to a mineralogy course. However,through this project students learn the techniquesrequired to investigate any one rock in detail. Ideally,they may then apply those same techniques to learnabout a variety of rocks and minerals as they continuetheir studies in geology.

ACKNOWLEDGMENTS

I extend many thanks to Adrian Holmes and CristinAshmankas, two Eckerd College students who con-tributed to this manuscript. Adrian summarized hisexperience with the building stone project (Figure 2) andCristin provided a portion of her final report (Figure 4). Ialso thank Karen Bartels and Jennifer Thomson whosereviews greatly improved this document.

REFERENCES

Dragovich, D., 1978, Building stone and its use in rockweathering studies: Journal of Geological Education, v. 27, p. 21-25.

Fickies, R.H., 1986, Building Stones of the Empire StatePlaza: A Walking Tour: Albany, New York, NewYork State Geological Survey, 13 p.

Hannibal, J.T., and Park, L.E., 1992, A guide to selectedsources of information on stone used for buildings,monuments, and works of art: Journal of GeologicalEducation, v. 40, p. 12-24.

Hebrank, A.W., 1989, The Geologic Story of the St. LouisRiverfront: A Walking Tour: Missouri Department of Natural Resources, Special Publication 6, 50 p.

Hoskin, P.W.O, 2000, Urban Outcrops and the lunchtimepetrology field trip: Journal of Geological Education,v. 48, p. 573.

Judson, S., Bonini, W.E., Rhodes, D.D., and Rossbacher,L.A., 2000, The Lab Book: Problem Solving inGeology: Upper Saddle River, New Jersey,Prentice-Hall, 266 p.

Kemp, K.M., 1992, Walking tours of building stones forintroductory geology courses: Journal of GeologicalEducation, v. 40, p. 188-193.

Kvale, E.P., Powell, R.L., and McNerney, M.J., 2000, Theart, history, and geoscience of Hindostan whetstonegravestones in Indiana: Journal of GeologicalEducation, v. 48, p. 337-342.

Winkler, E.M., 1997, Stone in Architecture: Properties,Durability: New York, Springer-Verlag, 313 p.

Withington, C.F., 1998, Building Stones of Our Nation’sCapital: U.S. Government Printing Office, 36 p.


Figure 3. During the walking tour, students examine the dolomite marble columns of the downtown St.Petersburg Post Office.

Figure 4. A cover letter created by one student“consultant” for her “client”.