Skyline Geology: A Self-Guided Walking Tour of Downtown Houston’s Buildings (Jones Loop)

We’ve taken hundreds of pictures and have tried to find as many facts and best guesses as possible.  If you do one of our self-guided tours on your own and find more accurate information, we’d be happy to update it here.  We proudly bring to you one of several self-guided walking tours: Jones Loop.  There’s a condensed free PDF guide at the bottom of this post for easy printing or smart phone viewing.  And if you need a super quick geology precursor, you can find that here: Geology Basics: For the Casual Observer or Amateur Enthusiast.  Enjoy, fellow rock lovers!

BAYOU PLACE – 510 TEXAS

Building Accent 1

Mixed landscaping stones

• Sandstone (fluvial or marine sedimentary)
• Quartzite and/or marble (low grade metamorphic)
• Slate (low grade metamorphic)

Observed: The quartzite and/or marble appears to have dolomite growth on some of the edges (pink anhydrous carbonate mineral).  The slate has typical weathering features showing iron oxidation.

Building Accent 2

Unknown dark stone, could be concrete, could be well sorted conglomerate in alternating rough and sliced bricks

717 TEXAS

Granite (cream and tan, mafic igneous)

Maybe St. Cecilia granite from Brazil, also known as Giallo Napoleone, quarried in Espirito Santo

If Giallo, then age is late Neoproterozoic to Cambrian (635-485my)

Fun Fact

Sharing the same block is the Lancaster Hotel that recently underwent a 10 month renovation post Hurricane Harvey.  It is an example of Regency style and in 1984, the hotel received Recorded Texas Historic Landmark status.  In 2010, it was accepted into the prestigious Historic Hotels of America representing the Jazz Age.

Porphyritic texture, alkaline granite containing garnets

Alkaline granite: Rich in potassium feldspar

Observed: Moth light and dark varieties of St. Cecilia present.  Most of building is light/white St. Cecilia, finer grained dark granite as accent, could even be Caledonia Granite (trade name) from Canada or Brazil.

Building

Observed: Garnets, likely spessartine, a manganese aluminum variety

Pavement

Light and dark granites, unpolished

Light granite is a visual match to building.  Dark granite could be Caledonia Granite (trade name) from Canada or Brazil.

PARKING LOT AT MILAM/TEXAS

Parking Lot Half-Wall

Granite or Quartz Monzonite (intermediate igneous)

Color matched: Coldspring Academy Black (trade)

From Clovis, California (assumed)

Mesozoic, possibly Jurassic (201-145my)

Observed: less than 20% quartz grains, equal amounts of biotite, hornblende, orthoclase and plagioclase feldspar (generally)

CHASE TOWER – 600 TRAVIS

Building

Granite (grey, mafic igneous)

Barre Gray Granite from Vermont/Quebec, Canada

Devonian (419-359my)

Medium grained, even textured, biotite granite containing quartz and orthoclase feldspar.  Very weather resistant.

Fun Facts

The granite was shipped to Italy, cut, and shipped back. There’s enough granite on the tower to fill 11 football fields. At the entrance of the building is a multi-colored sculpture entitled “Personage with Birds”, which was designed by painter and sculptor Joan Miró.

Pavement

Pink Laurentian granite from Canada

PreCambrian (>541 my)

Veined (bottom left)

Fountain

Granite (mafic igneous)

Maybe Barre Gray Granite, looks very similar

Pavers/Pavement

Granite (mafic igneous)

Pink mineral is potassium feldspar

Veined, some composition/texture zoning (bottom right)

JONES HALL – 615 LOUISIANA

Building

Tufa (Travertine, continental sedimentary)

Travertino Romano (trade) from Tivoli near Rome in Italy

Also known as Romano Classico or Travertine Classico

Tufa/Travertine: formed by algae/calcium carbonate in hot springs, phytoherms (freshwater reefs) and thrombolite-stromatolites; not to be confused with tuff/tufo (igneous)

Observed: stromatolite patterns/precipitation growth dominant feature (thin dashed lines, left), some vugs partially to fully filled with more transparent cement, some soft fault/like displacement before lithification (thick dashed lines, left)

Fun Facts

It occupies and entire city block and features a white Italian marble exterior with eight story tall columns.  It won the 1967 American Institute of Architects’ Honor Award.

Accent

Granite (mafic igneous)

PENNZOIL PLACE – 700 MILAM

Building Accents

Granite (pink, mafic igneous)

Sardinian Pink (Rosa Beta) from Alta Gallura area (Tempio, Calangianus, Aggius and Luras) in Sardinia

Upper Paleozoic (Carboniferous and Permian, 359-252my)

Observed: Potassium feldspar (pink), plagioclase feldspar (white), quartz (grey), hornblende (black), and biotite (black).

Fun Facts

The building itself consists of two 495 ft  trapezoidal towers placed ten feet apart and sheathed in dark bronze and aluminum.  It was named “Building of the Decade” in 1975 by the New York Times architecture critic Ada Louise Huxtable.  The base of the Statue of Liberty is also Sardinian Pink Granite from La Maddalena, Sardinia.

BANK OF AMERICA CENTER – 700 LOUISIANA

Building/Pavement/Accents

Granite (pink-red, mafic igneous)

Balmoral red granite from Vehmaa-Taivassalo area in Finland (or Sweden)

Precambrian (>541my)

Medium grained, uniform, granite containing brick-red potassium feldspar, dark smoky quartz, plagioclase feldspar, biotite, and hornblende

One rock with 4 finishes

• Building base and rolled moldings polished high gloss finish
• Building honed finished
• Insets hammered finished
• Pavement flame finished

Fun Facts

Gables inspired by canal houses of The Netherlands. It represents one of the first significant examples of postmodern architecture construction in Downtown Houston.

Building

The 4 types of granite finishes on this building

• Building Base: High gloss polished finish enhances a stone’s natural pattern and colors
• Building: Honed finish has a smooth surface, buffed or matte appearance but not polished
• Insets: Bush hammered finish artificially creates textured surface
• Pavement: Flame finish is heated retaining the rough texture of the stone but resistant to moisture and shoes in Downtown Houston

BOB CASEY FEDERAL COURTHOUSE – 515 RUSK

Building

Fossiliferous Limestone (marine sedimentary)

Cordova Shell from Austin (quarry/trade)

Whitestone Lentil (geo)

Walnut Formation

Middle Cretaceous (105my)

Fun Facts

Also found at City Hall in Downtown Houston and in the National Museum of Natural History in Washington D.C.

Fossils Observed: Trigonia, Turitella, Crinoid, Rudist, Bryozoan

Bricks appear to be artificial but match fossiliferous panels in color

Building

Trigonias with Bryozoan

HOBBY CENTER FOR THE PERFORMING ARTS – 800 BAGBY

Pavement Accent

Granite (pink-brown, mafic igneous)

Could be Baltic Brown (trade) or similar

Sign Accent

Unknown, could be Black Pearl Granite (trade) from India

Download Free PDF Skyline Geology: A Self-Guided Walking Tour of Downtown Houston’s Buildings (Jones Loop) here: DowntownGeologyJonesPDF

Published Walking Tours

Skyline Geology: A Self-Guided Walking Tour of Downtown Houston’s Buildings (City Hall Loop)

Tunnel Geology: A Self-Guided Walking Tour of Downtown Houston’s Buildings (Red Loop)

Skyline Geology: A Self-Guided Walking Tour of Downtown Houston’s Buildings (Hyatt Loop)

Tunnel Geology: A Self-Guided Walking Tour of Downtown Houston’s Buildings (Yellow Tunnel)

Skyline Geology: A Self-Guided Walking Tour of Downtown Houston’s Buildings (Jones Loop)

Tunnel Geology: A Self-Guided Walking Tour of Downtown Houston’s Buildings (Teal Tunnel)

CONTRIBUTORS

Sheila Echols-Smesny holds a Bachelor of Science in Geology from Sam Houston State University, an Executive MBA from Texas Woman’s University, and works at an oil & gas company in Houston.  Red Shoes. Red Wine. is Sheila’s travel, lifestyle, & hobby blog.

Christen Peevy holds a Bachelor of Science in Geology from University of Oregon and works at an oil & gas company in Houston.  Christen’s lifestyle blog is Short Sweet & Lovely.

Katy Mainwaring holds a Bachelor of Science in Geology from Texas Tech University and works at an oil & gas company in Houston.  Katy teaches geology with Sheila for Texas Parks and Wildlife Becoming an Outdoors Woman program.

BEFORE YOU GO

Safety

• Look up, not at your phone, when navigating downtown
• Please be mindful of the traffic lights, pedestrian signals, bike lanes, and buses
• Buses make frequent stops and can sometimes hop curbs
• Some curbs, pavements, and streets may be uneven

Etiquette

• Please review the walking guide prior to arriving downtown to maximize time spent on the tour
• Please be mindful of downtown employees and keep slower pedestrian traffic to the right so they can go about their business
• Try to walk in pairs if walking around downtown as a group
• If approached by a homeless person, try to be firm but respectful

REFERENCES

• Houston Geological Society, 1995, Walking Tour of Downtown Houston Building Stones: Research Committee, Philip W. Porter
• Houston Gem and Mineral Society, Houston Geologic Society, 2008, Walking Tour – Houston Building Stones, Neal Immega
• Fox, Stephen, Houston Architectural Guide, Second Edition, American Institute of Architects/Houston Chapter and Herring Press, Houston, 1990.
• Rock Building Stones: Downtown Geology & Materials Tour hosted by AIA Houston (2018) https://aiahouston.org/v/site-page/ArCH-WalkingTours/Rock-Building-Stones/5v/
• https://www.houstonarchitecture.com/Building/523/The-Bank-of-America-Center.php
• http://www.jsjgeology.net/Granite-Porphyritic-Granite-decorative-stone.htm
• https://www.daltile.com/inspiration-and-tips/inspiration-and-diy/polished-flamed-or-honed-granite-a-guide-to-different-finishes
• Wikipedia
• Geology.com