Philippinites, or rizalites are tektites found in the Philippines. They are considered to be about 710,000 years old on the average[1] and generally ranging in size from millimeters to centimeters.[2] Their age corresponds with the age of other tektites in the Australian strewn tektite field.[1] In 1964, a very large philippinite, weighing 226.3 grams (0.499 pounds) with dimensions 6.5 x 6.2 x 5.2 cm, was purchased by the University of California, Los Angeles Department of Astronomy.[3][4] The heaviest philippinite ever found weighs 1,281.89 grams (2.8261 pounds) in its splash-form[Note 1], which is also the heaviest tektite of this kind.[5]
Etymology
editThe term rizalite was named after the Philippine province of Rizal where the first black tektites were rediscovered in October 1926 at Novaliches (which was then part of Rizal).[3] Although, it was only in 1928 that the term was proposed by American anthropologist H. Otley Beyer, dubbed as the father of Philippine tektite studies, to refer to tektites found in the Philippines.[6] Philippinite has become the more favored term because other tektites were found in other areas of the Philippines such as the Bicol region and the town of Anda in the province of Pangasinan.[6][7] Some early authors referred to Philippine tektites as "obsidianites" but that too has fallen out of use due to the introduction of the term philippinite by succeeding authors.[8]
Uses
editIn ancient Philippines, tektites were used by early settlers in the Philippines as arrowheads and other tools[3] as well as decorative purposes.[1] During the Philippine Iron Age, due to the polish features of philippinites found in graves, it was evidenced that philippinites were used as amulets or charms.[3][8] In modern times, it is generally used as a collector's item.[2]
Composition
editThe following table details the chemical composition of philippinite:[3]
| Oxides | Content (in weight percentage) |
Number of determinations |
|---|---|---|
| SiO2 | 70.66-71.64 | 4 |
| TiO2 | 0.63-1.04 | 4 |
| Al2O3 | 12.08-13.52 | 4 |
| Fe2O3 | 0.59-2.03 | 3 |
| FeO | 3.03-5.32 | 4 |
| MnO | 0.08-0.16 | 4 |
| CaO | 2.95-3.42 | 4 |
| MgO | 2.23-3.65 | 4 |
| Na2O | 1.21-1.66 | 4 |
| K2O | 1.69-2.28 | 4 |
| H2O+ | 0.15-0.63 | 4 |
| H2O− | Traces | 1 |
| P2O5 | 0.10-0.18 | 3 |
Notes
edit- 1 Splash-form tektites are tektites that are shaped like spheres, ellipsoids, teardrops, dumbbells, and other forms.[9] They have shaped this way due to the ejecta or splash of silicate liquid following a meteorite impact, scattering them to a distance up to thousands of kilometers.[10]
References
edit- ^ a b c "Tektites". www.nationalmuseum.gov.ph. National Museum of the Philippines. February 10, 2014. Retrieved 2019-02-06.
- ^ a b "Philippinites: Rizalites, Bikolites & Andas!!!". www.tektitesource.com. Retrieved 2019-02-06.
- ^ a b c d e Ye. S. Burkser; et al. (June 1964). "METEORITICS NO. 19" (PDF). United States Department of Defense - Defense Technical Information Center. National Aeronautics and Space Administration. pp. 49–50. Archived (PDF) from the original on April 19, 2021. Retrieved 6 February 2019.
- ^ Leonard, F. C. (1955). "A Large Tektite from the Philippines". Meteoritics. 1 (3): 357. Bibcode:1955Metic...1..357L.
- ^ "Largest Tektites - TEKTITES". www.tektites.co.uk. Retrieved 2019-02-06.
- ^ a b Lehrman, Norm (September 1, 2018). "Norm's Tektite Teasers: (Part two of three): Philippinites: The Classics". Meteorite Times Magazine. Retrieved 2019-02-06.
- ^ Whymark, Aubrey (2017). "TEKTITES INFO - Local Tektite Names". www.tektites.info. Retrieved 2019-02-06.
- ^ a b Baker, George (1 July 1959). "Memoirs of the National Museum of Victoria - TEKTITES" (PDF). Museums Victoria. pp. 13, 187. Retrieved 6 February 2019.
- ^ "tektite | Properties, Distribution, & Facts". Encyclopedia Britannica. Retrieved 2019-02-07.
- ^ Butler, S.L.; Stauffer, M.R.; Sinha, G.; Lilly, A.; Spiteri, R.J. (25 January 2011). "The shape distribution of splash-form tektites predicted by numerical simulations of rotating fluid drops". Journal of Fluid Mechanics. 667. Cambridge University Press: 358–368. Bibcode:2011JFM...667..358B. doi:10.1017/s0022112010005641.