THE GUANGALA AND
MANTEÑO-HUANCAVILCA
SHELL ORNAMENT
PRODUCTION METHODS
Sydney Cargill, Isha Chavva, Shannon Duffy, Julia
Flores, Jennifer Mao, Gabrielle Shvartsman, Cindy
Weng, Sharmitha Yerneni
Peru
Spondylus
Guangala 200 B.C.- 600/800 A.D.
Manteño-Huancavilca 700/900 A.D. - 1530 A.D.
● Samples were recovered
from two main sites
○ Site 47 near El Azúcar
(Guangala)
○ Site T2-2 near Chanduy
(Manteño-Huancavilca)
How did they get from a Spondylus shell to a 4 mm bead?
Hypotheses
1. Shell reduction - combination of sawing and
knapping processes
2. Drilling - comparing Guangala and
Manteño-Huancavilca beads
3. Grinding - added to shell reduction process
during Manteño-Huancavilca
Shell Reduction:
Sawing
archaeological samples suggestive of sawing
experimental
archaeological
Boiling and the Moh’s Hardness Scale
Hardness (Moh’s Hardness Scale)
Trial 1
Trial 2
Trial 3
After Boiling 5
min.
After Cooling 5
min.
After Boiling 5
min.
After Cooling 5
min.
After Boiling 5
min.
After Cooling 5
min.
2
3
3
3-4
3
3
Calcite, Shell, Gypsum
(Top to Bottom)
Fluorite, Shell, Calcite
(Top to Bottom)
Fluorite, Shell, Calcite
(Top to Bottom)
Shell Reduction:
Knapping
Piece that was knapped off from the cortex
archaeological
experimental
Drilling:
Bead
Perforation
Analysis
Scanning Electron
Microscopy (SEM)
Comparison of Drilling Methods
Guangala Bead
Manteño-Huancavilca Bead
Although the drill hole rims of both the Guangala and M-H beads were smooth, the interior
cavity of the M-H bead was smoother than that of the Guangala bead.
Shell Refinement:
Grinding
sandstone
Experimental Shell Sample 1 (circular method)
Experimental Shell Sample 2 (back-and-forth method)
Circular Method
Back-and-Forth Method
Archaeological Shell Sample
Guangala Bead
Circular Method
Manteño-Huancavilca Bead
Guangala Bead
Back-and-forth Method
Manteño-Huancavilca Bead
Fracture Method
● Find fracture lines
● Obsidian pieces to cut
●
●
●
●
Under five minutes
No grit, lemon, or boiling
1mm deep cut
considerably efficient
Experimental
● Compared ridges:
experimental and original
● pre-existing vs. created
fractures
● Fracture creation risky
● More research
Original
Future Research
Conclusion
Acknowledgements
We would like to thank:
Independent College Fund of NJ/Johnson & Johnson
AT&T
Bayer Healthcare
The Overdeck Family Foundation
NJGSS Alumnae, Parents, and Corporate Matching Funds
Board of Overseers, New Jersey Governor’s Schools
The State of New Jersey
Drew University
Dr. Maria Masucci
Dr. Adam Cassano
Dr. Steve Surace
Kaushaly (Shelly) Patel
Yumi Kouh
References
Spondylus shell and beads:
http://news.nationalgeographic.com/news/2013/12/131203-chimutomb-ancient-peru-nobles-sacrifices-archaeology-science/
Red Spondylus necklace:
http://nga.gov.au/exhibition/Incas/Default.cfm?IRN=231264&BioArtistIR
N=91411&MnuID=3&GalID=3&ViewID=2
Moh’s hardness scale:
http://www.nature.nps.gov/geology/education/concepts/minerals.cfm
SEM picture
http://ares.jsc.nasa.gov/Laboratories/kr_laboratories/SEM.cfm
THANK YOU!