CC BY 4.0Gacayan, Daniel B.Lacuata, Shaira Jane F.Gatchallan, Sherilly G.Peralta, Hanna Sophia C.Rimpillo, Ronalyn R.2026-04-162026-04-162023-05Lacuata, S. J. F., Gatchallan, S. G., Peralta, H. S C. & Rimpillo, R. R. (2023). Development of oyster (Ostreidae) shells as chalk. [Unpublished Undergraduate Thesis]. Don Mariano Marcos Memorial State University – Mid La Union Campus, City of San Fernando, La Union. Lakasa ti Sirib, DMMMSU Institutional Repository.https://lakasa.dmmmsu.edu.ph/handle/123456789/1325Full textOyster shell is a type of sea shell that has naturally occurring component of calcium carbonate, that is primarily used in making chalk. This study aimed to: standardize the formulation and process, determine the junctional attributes, microstructural qualities, and production cost of developed oyster shell chalk. The research design used were: Researchers used experimental method for the standardized formulation of oyster shells as chalk, in which researchers performed six different trials, and a descriptive study design is used for functional attributes of the oyster shell chalk for median computation. Treatment 2 has the highest median while Treatment 1 has the lowest median. The oyster shell chalk has a mean breaking strength of 10.3 N (load of 1.05 kg) and standard deviation of 2.84 N (load of 0.290 kg), ranges 11 mm in diameter and 84.1 mm long. The total production cost is comparable with the leading brands.xii, 64 p.: ill. (col.)enOyster shell -- ChalksWriting materials – ChalkThesis