## 6 Conclusions  
This study investigates how the petrogenetic characteristics of ultramafic rocks from Veria-Naousa and Gerania ophiolite complexes are able to predict the final behaviour of ultramafic aggregates as well as to evaluate their suitability as concrete aggregates. The main conclusions of the study are summarized below:  
* There is a significant difference in the degree of alteration between the rocks of the two complexes (the Veria-Naousa and Gerania ophiolite complexes), with those of the Gerania ophiolite complex being in particular fresher than those of the Veria-Naousa ophiolite complex. * The mineralogical, petrographic and chemical characteristics are in accordance with the physical-mechanical and physico-mechanical characteristics of the studied ultramafic rocks. * The introduced chemical indices such as the 'fertility rate' (FR), the Ultramafic Rock Health Index (U.R.H.I.) and the Normalized U.R.H.I. (U.R.H.I\({}_{\text{N}}\)), assessing and quantifying the overall health conditions of the ultramafic rocks as well as the extent of serpentinization, are correlated with the engineering properties of the tested aggregate rocks and showed a strong relationship. * The genesis environment of the ultramafic rocks is the critical factor that determines their mineralogical, petrographic and chemical characteristics, which consequently determines the basic engineering properties of rocks that determine their suitability as concrete aggregates. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app12083990/s1](https://www.mdpi.com/article/10.3390/app12083990/s1)]([https://www.mdpi.com/article/10.3390/app12083990/s1](https://www.mdpi.com/article/10.3390/app12083990/s1)). Figure S1. (a) Ultramafic rocks derived from Veria-Naousa ophiolite complex; (b) Ultramafic rocks derived from Gerania ophiolite complex; (c) Uniaxial compressive strength test machine; (d) LA test machine; Table S1. Serpentine abundance of the studied rock samples from Veria-Naousa (SV) and Gerania (SG) ophiolite complex. The quantification errors calculated for each phase according to Bish and Post [66] are estimated to be \(\sim\)1%; Table S2. Representative geochemical analyses of peridotites from Veria-Naousa and Gerania ophiolite (*: below detection limit); Table S3. Main Physical, mechanical and physicochemical properties of tested ultramafic rock samples from Veria-Naousa (SV) and Gerania (SG) ophiolite complex; Table S4. The chemical indices F.R., U.R.H.I. and U.R.H.I.N of tested ultramafic rock samples from Veria-Naousa (SV) and Gerania (SG) ophiolite complex; Table S5. Representative electron microanalyses of spinel-group minerals from peridotites of Veria-Naousa (SV) and Gerania (SG) ophiolite complex (-: below detection limit). **Author Contributions:** Conceptualization, P.P. (Petros Petrounias); methodology, P.P. (Petros Petrounias), P.P.G., A.R. and P.L. ; software, P.P. (Petros Petrounias), A.S. and P.K. ; investigation, P.P. (Petros Petrounias), P.P.G., A.R., P.L., N.K., P.P. (Panagiotis Pomonis) and K.H. ; resources, P.P. (Petros Petrounias), P.P.G., A.R., A.S. and K.H. ; data curation, P.P. (Petros Petrounias), P.P.G., A.R., A.S., P.K., P.L. and P.P. (Panagiotis Pomonis); writing--original draft preparation, P.P. (Petros Petrounias), P.P.G. and A.R. ; writing--review and editing, P.P.P. (Petros Petrounias), P.P.G., A.R., A.S., P.L. and N.K. ; visualization, P.P. (Petros Petrounias) and P.K. ; supervision, P.P. (Petros Petrounias), P.P.G. and K.H. All authors have read and agreed to the published version of the manuscript. This research received no external funding. **Informed Consent Statement:** Not applicable. **Acknowledgments:** We kindly thank [PERSON] of the Laboratory of Electron Microscopy and Microanalysis, University of Patras for his assistance with the microanalyses and SEM micrographs. We kindly thank [PERSON] for his assistance in the fieldwork and for their whole contribution to this study.