This study examined rock types, rock colors, particle sizes, mineralogical and chemical composition, magnetic susceptibility, sizes, surface conditions and damage of flagstones of the trifurcated path at Jongmyo royal shrine in order to inquire into the petrological characteristics of flagstones of the trifurcated path at Jongmyo and the quarry which is assumed to be the production site of flagstone and conducted mineralogical composition, mineralogical contents ratio, petrochemistry analysis and magnetic susceptibility analysis for the comparison of its similarity to rocks of Seokmodo. In addition, it established standardization conditions of flagstones through the analysis of these data. The results of this study are as follows.
1. Trifurcated path at Jongmyo royal shrine is divided into six rock types such as pale gray fine to medium grained biotite granite, pale gray fine to medium grained hornblende biotite granite, pale pink medium to coarse grained biotite granite, pink medium to coarse grained biotite granite, schist and pegmatite and schist depending on rock colors, particle sizes and mineralogical composition, and pale gray fine to medium grained biotite granite is the major member of flagstone.
2. The average size of flagstone of the trifurcated path at Jongmyo royal shrine is 65 × 46cm (standard deviation 12 × 7cm).
3. According to surface conditions of flagstone, good condition was 34.7%, normal condition 41.4% and below normal condition 23.8%. Pale pink and pink flagstones of granite flagstones showed almost conditions below normal.
4. When flagstones of trifurcated path at Jongmyo and of Seokmodo were illustrated on IUGS classification in order to examine their mineralogical similarity, granite of flagstones at Jongmyo and biotite granite of Seokmodo were illustrated at the granite area.
5. In genetic classification, two granites were peraluminous I-type granite (indicating igneous origin), alumina langelier saturation index is massed within 1 ~ 1.1 and these two granites showed almost same content rate from petrochemical side.
6. Magnetic susceptibility measured from two granites was most prevailed within 1 × 10-3 SI, flagstone of the biotite granite showed very similar distribution to magnetic susceptibility of biotite granite at the north slope of Seokmodo and flagstone of hornblende biotite granite showed very similar distribution to magnetic susceptibility of biotite granite containing a small quantity of hornblende at the south slope of Haemyeongsan.
7. Standard of granite which can be used as major member of flagstone should be pale gray fine to medium grained biotite granite, composition minerals should belong to granite on IUGS classification with quartz, plagioclase, microcline, perthite and biotite. In addition, it will be optimal that SiO₂component is over 70wt.% and magnetic susceptibilityis within 0.1 × 10-3 SI.