The red-colored granite has the most diverse type among building granites in China, and among them, the dark-red colored granites are the most dominate. The dark-red colored granites are primarily dark or flesh-red in appearance, accompanied by interspersed grey, white, and black. Many well-known dark-red type granites, such as “Cengxi Red”, “Sichuan Red”, “Guilin red” and “Yongding Red” are all mined from building granite deposits based on their geographic names (Wang et al., 2021; Zhan and Chen, 2021; Zou et al., 2024). Here we collect “Cengxi Red” as a representative.

The “Cengxi Red” is discovered in the Changgangding granitic pluton from Cengxi City, Guangxi Province (Figures 1a,b). It is a Jurassic granite with zircon U-Pb ages of 158.5 ± 0.9 Ma (Zou et al., 2024). The Changgangding pluton is a composite granite pluton composed of syenogranite, monzonitic granite, granodiorite, granite porphyry, and monzodiorite. The “Cengxi Red” granitoid ore is all produced in syenogranite, with lithology of medium-to coarse-grained biotite syenogranite. The sample is flesh-red colored, with medium-to coarse-grained granitic texture, porphyritic-like texture, and massive structure (Figure 2a). The mineral composition is mainly K-feldspar, quartz, plagioclase, and biotite, with accessory minerals of zircon and magnetite (Figure 2b).

The light-red colored granites also have abundant types, but they are relatively fewer in types compared to the dark-red colored granites. The dark-red colored granites are primarily light flesh-red or pink in appearance, accompanied by interspersed grey, white, and black. Well-known light-red type granites in China include “Baihujian Red”, “Lianjiang Red”, “Anxi Red”, “Lianzhou Red” and “Huidong Red” (Cheng and Wang, 2010; Wang et al., 2021; Zhan and Chen, 2021). Here we collect “Baihujian Red” as a representative.

The “Baihujian Red” is discovered in the Yangfang granitic pluton from the suburbs of Beijing city (Figures 1a,c). It is a Cretaceous granite but lacks high-precision dating results (Cheng and Wang, 2010). The Yangfang pluton is also a composite granite pluton composed of monzonitic granite, monzodiorite, and alaskite. The “Baihujian Red” granitoid ore is all produced in monzonitic granite, with lithology of medium-to coarse-grained biotite monzonitic granite (Figure 2c). The sample is pink-colored, with medium-to coarse-grained granitic texture and massive structure. The mineral composition is mainly quartz, K-feldspar, plagioclase, and biotite, with accessory minerals of zircon, titanite, and garnet (Figure 2d).

The grey and black-white colored granites constitute another color system of the building granite, which are relatively fewer in types compared to the red colored granites. Among them, the grey colored granites are relatively fewer in types compared to the black-white colored granites. The grey colored granites are commonly grey in appearance with interspersed black. Well-known grey type granites in China are mostly not named by their geographic location, but by their appearances instead, such as “Gingili Grey” and “Antique Grey” (Zhang et al., 2012; Yue, 2020; Wang et al., 2021; Zhan and Chen, 2021), Here we collect “Gingili Grey” as a representative.

The “Gingili Grey” is discovered in the Jingde granitic pluton from Jingde County, Xuancheng City, Anhui Province (Figures 1a,d). It is a Cretaceous granite with zircon U-Pb ages of 139.7 ± 1.3 Ma (Zhang et al., 2012). The Jingde pluton is a composite granite pluton composed of four stages of intrusions, including early two stages of granodiorite and late two stages of monzonitic granite. The “Gingili Grey” is discovered in the granodiorite, with lithology of fine-to medium-grained biotite granodiorite, occasionally containing mafic microgranular enclaves (Figure 2e). The sample is grey-colored, with fine-to medium-grained granitic texture and massive structure. The mineral composition is mainly plagioclase, quartz, K-felspar, biotite, and minor hornblende, with accessory minerals of zircon, titanite, apatite, and magnetite (Figure 2f).

The black-white colored granites have more types compared to the grey colored, and they are extremely fashionable and widely used as building granite. The black-white colored granites have only black and white colors in appearance and can be named as “White”, “Black” and “Flower” according to different proportions. The “White” type is dominated by white color in appearance, the “Black” type is dominated by black color in appearance, and the “Flower” type has nearly equal proportions of white and black colors in appearance. Well-known black-white type granites in China are named by their geographic locations and appearances, such as “Pearl Flower”, “Black-white Flower”, “Gingili White”, “Quanzhou White”, “Tongan White” and “Fuding Black” (Hu, 2019; Wang et al., 2021; Zhan and Chen, 2021; Ju, 2023). Here we collect “Pearl Flower” as a representative.

The “Pearl Flower” is discovered in the Nansu granitic pluton from Nansu Village, Laizhou City, Shandong Province (Figures 1a,e). It is a Cretaceous granite with zircon U-Pb ages of 116.8 ± 1.0 Ma (Ju, 2023) and 121.3 ± 2.1 Ma (Hu, 2019). The Nansu pluton is a small granitic intrusion composed of granodiorite and monzonitic granite. The “Pearl Flower” was discovered in the granodiorite, with lithology of fine-grained biotite granodiorite. The sample is black-white colored, with fine-grained granitic texture and massive structure (Figure 2g). The mineral composition is mainly plagioclase, K-feldspar, quartz, biotite, and minor hornblende, with accessory minerals of zircon, titanite, apatite, allanite, and magnetite (Figure 2h).

Traditional granites have been classified as I-, S-, A-, and M-type based on their protoliths and geochemical features (Chappell, 1974; White and Chappell, 1983; Whalen, 1985; Whalen et al., 1987; Ghoneim et al., 2010). However, adakitic rocks also contain rocks of granite type, and which can have distinct petrogenesis compared to traditional granites. Thus, to clearly understand the petrogenesis of the different granites in this study, we have to reveal their petrogenetic type.

M-type granites are defined as granite that were directly derived from mantle mafic magma, which are commonly developed in oceanic crust rather than continental crust, such as oceanic islands and mid-ocean ridges (Whalen, 1985), and can be excluded in this study.

S-type granite is defined as granite that forms by the remelting of sedimentary rocks, which frequently occurs in the upper crust (Chappell et al., 2012). In this case, S-type granite usually contains abundant Al-rich minerals such as muscovite, garnet, and cordierite, which would produce high A/CNK values (>1.1) (Clemens, 2003; Zen, 2003; Ishihara, 2007). In addition, S-type granite usually has high P₂O₅ content because apatite reaches saturation in metaluminous and mildly peraluminous magmas but remains highly soluble in strongly peraluminous melts (Chappell, 1999). In this study, the “Cengxi Red”, “Baihujian Red”, “Gingili Grey” and “Pearl Flower” granitoids all have low P₂O₅ contents (<0.2) and low A/CNK values (<1), with no Al-rich minerals observed, excluding an S-type affinity.

I-type granite is defined as granite that forms by the re-melting of igneous rocks, which frequently occurs in the lower crust (Chappell and White, 2015). In this case, the I-type granite is often granodiorite and contains abundant hornblende. Moreover, I-type granite usually has low A/CNK (<1.1) and K₂O/Na₂O ratios (<1) (Wang et al., 2001). As mentioned above, since apatite is soluble in peraluminous melts but insoluble in metaluminous melts, the concentration of P increases with increasing SiO₂ in S-type melts but decreases with increasing SiO₂ in I-type melts (Huang et al., 2013). In this study, all granites have low A/CNK values (<1), but the “Cengxi Red” and “Baihujian Red” granitoids have relatively higher K₂O/Na₂O ratios (1.04–1.99) than the “Gingili Grey” and “Pearl Flower” granodiorites (0.72–1.35). In terms of petrographic features, the “Gingili Grey” and “Pearl Flower” granodiorites belong to granodiorite rock type with hornblende observed, and the “Gingili Grey” granodiorites have low SiO₂ contents which plot in the granodiorite field. Additionally, in the SiO₂ vs. P₂O₅ diagram (Figure 5g), the “Gingili Grey” and “Pearl Flower” granodiorites follow an I-type trend. Therefore, the “Gingili Grey” and “Pearl Flower” granodiorites exhibit an I-type affinity, while the “Cengxi Red” and “Baihujian Red” granitoids do not. However, an adakitic affinity cannot be fully excluded.

A-type granite was proposed to define granitic rocks with characteristics of“Alkali”, “Anhydrous”, and “Anorogenic” (Loiselle and Wones, 1979), which means that A-type granites commonly have high SiO₂, K₂O + Na₂O, FeO^T/MgO and low CaO content, and are enriched in Ga, Zr, Nb, Ta, Y, Ce, F, REE and depleted in Ba and Sr (Douce and Alberto, 1997; Loiselle and Wones, 1979; Whalen et al., 1987; Ghoneim et al., 2022). In the diagrams of Zr + Nb + Ce + Y vs. (K₂O + Na₂O)/CaO and Zr + Nb + Ce + Y vs. FeO^T/MgO (Figures 6a,b), the “Gingili Grey” and “Pearl Flower” granodiorites plot in the unfractionated I- and S-type granite field, while the “Baihujian Red” and “Cengxi Red” granitoids plot at the edge of the fractionated I- and S-type granite and A-type granite fields. An important feature of A-type granites is that they usually have much higher crystallization temperatures than I-type and S-type granites, which usually reaches 760 °C or even higher (Skjerlie and Johnston, 1993; King et al., 1997). Calculating the crystallization temperatures of the “Cengxi Red”, “Baihujian Red”, “Gingili Grey” and “Pearl Flower” granitoids using the zirconium saturation thermometer, we yielded crystallization temperatures of the “Cengxi Red” (795 °C–850 °C), “Baihujian Red” (801 °C–817 °C), “Gingili Grey” (599 °C–799 °C) and “Pearl Flower” (613 °C–805 °C) granites. The “Cengxi Red” and “Baihujian Red” granitoids have relatively higher temperatures than the “Gingili Grey” and “Pearl Flower” granodiorites, indicating an A-type affinity. Petrographically, A-type granites usually contain alkali feldspar and lack inherited zircon cores. The “Cengxi Red” and “Baihujian Red” granitoids have lithologies of syenogranite and monzonitic granite, which contain abundant K-feldspars, also consistent with A-type granite features.

Granodiorite can either form in I-type granites or adakitic rocks, and these two types of rock have similarities and differences. The most common similarities of I-type granites and adakitic rocks are that they can both form granodiorite which contains hornblende, with relatively low SiO₂ contents (<70 wt%) and A/CNK values (<1.1) (Huang et al., 2013; Yang et al., 2016). However, adakitic rocks have characteristics of high Sr/Y and (La/Yb)_N ratios with low-Y contents and Yb_N values, which are different compared to the I-type granites (Xie et al., 2024; Zi et al., 2024). In the Y vs. Sr/Y and Yb_N vs. (La/Yb)_N diagrams (Figures 7a,b), the “Gingili Grey” granodiorites are plotted in the normal andesite-dacite-rhyolite field, which can exclude an adakite affinity. Conversely, the “Pearl Flower” granodiorites are plotted in the adakite field, but they have high K₂O/Na₂O ratios, low Al₂O₃ and MgO contents, and high ⁸⁷Sr/⁸⁶Sr ratios (Hu, 2019; Ju, 2023), which are also not comparable to adakitic rocks.

In summary, the “Cengxi Red” and “Baihujian Red” granitoids are A-type granites, while the “Gingili Grey” and “Pearl Flower” granodiorites are I-type granites.

The Spanish samples failed to analyze trace element compositions, making it difficult to reveal their petrogenetic type and magma source. However, major element compositions and petrographic characteristics can more or less reflect some of their identities. First of all, although the Spanish granites contain a certain content of muscovite, they are not entirely muscovite granites, and their A/CNK values (<1.1) are not high, indicating they are unlikely S-type granites (Clemens, 2003; Zen, 2003; Ishihara, 2007). Furthermore, their extremely high Na₂O and K₂O contents imply their high alkaline features, which also correspond to their high alkali feldspar proportion, making them highly approximate to A-type granites (Whalen et al., 1987; Ghoneim et al., 2022). In the diagrams of SiO₂ vs. Na₂O + K₂O-CaO (Figure 3c) and K₂O vs. Na₂O (Figure 6c), the Spanish samples are plotted in the A-type granite fields, which is quite similar to the “Cengxi Red”, “Baihujian Red” and “Gingili Grey” granitoids. However, when we calculate their crystallization temperatures, we find that their temperatures (680 °C–798 °C) are not so high, and they also do not conform to traditional A-type granites (Skjerlie and Johnston, 1993; King et al., 1997). Additionally, the Spanish samples have tested Rb₂O, SrO and ZrO₂, including in their major elements. When we inspect these three elements, they have relatively high Rb contents (155–430 ppm), but their Zr contents (44–148 ppm) are not so high. It seems their relatively moderate incompatible elements are also inconsistent with A-type granite (Xiao et al., 2023). Finally, some of the Spanish samples contain mafic minerals (amphibole). Although they have relatively high P₂O₅ contents and K₂O/Na₂O ratios (>1), they show low A/CNK values (<1.1), low crystallization temperatures (680 °C–798 °C), and moderate to high SiO₂ contents, which are more likely to conform to I-type granites. Thus, we tend to deduce that the Spanish building granites are I-type granites with relatively high alkaline, P and Rb contents.

A-type granites are considered to be formed either by partial melting of lower crustal protoliths or directly originating from mantle-derived magmas (Huang et al., 2011; Zheng et al., 2017; Li et al., 2021). To distinguish these origins, A₁-and A₂-subtypes have been proposed according to their different sources and tectonic settings. The A₁-type granite is related to an intracontinental rift valley or a mantle plume, usually formed by partial melting or fractional crystallization of mantle-derived basalt protoliths (Mao et al., 2013; Zhang and Zhang, 2014); the A₂-type granite is related to back-arc extension or postorogenic extension, usually formed by partial melting of lower crustal granulites, with or without the hybridization of mantle-derived mafic magmas (Liu et al., 2021; Xiao et al., 2023). In the diagrams of Y/Nb vs. Yb/Ta, Y/Nb vs. Ce/Nb, Nb-Y-Ce and Nb-Y-3Ga (Figure 9), the “Cengxi Red”, and “Baihujian Red” granitoids are plotted in the A₁-type and OIB-like fields, or just at the boundary line of the A₁-and A₂-type, indicating they are more likely related to mantle-derived basalts.

Although the “Baihujian Red” granitoids lack isotope data, the “Cengxi Red” granitoids show zircon εHf(t) values of −4.40 to 1.79, which are slightly higher than the average lower crust but lower than the depleted mantle (Zou et al., 2024). Both the “Cengxi Red” and “Baihujian Red” granitoids have Nb/U, Nb/Ta, and Nb/Th (Nb/U = 11∼21, Nb/Ta = 10∼22, and Nb/Th = 1.5∼3.1) ratios between those of the primitive mantle (Nb/U = 30, Nb/Ta = 17.5, and Nb/Th = 1) and the continental lower crust (Nb/U = 10, Nb/Ta = 11∼12 and Nb/Th = 3). Previous studies have proposed that the alkali feldspar granite could likely be generated by two mechanisms, including: (1) asthenosphere mantle-derived basalt magma undergoing extensive fractional crystallization (±assimilation) (Mao et al., 2013; Zhang and Zhang, 2014), and (2) asthenosphere mantle-derived basalt magma injecting into the shallow magma chamber of the volcanic rocks and the mixed magma undergoing fractional crystallization (Li et al., 2021; Xiao et al., 2023). Considering that both the “Cengxi Red” and “Baihujian Red” granitoids have coexisted intermediate rocks and mafic microgranular enclaves (Cheng and Wang, 2010; Zou et al., 2024), we consider that the “Cengxi Red” and “Baihujian Red” granitoids may have originated from an OIB-like source remaining in the lower crust, probably basaltic granulites, with injected asthenosphere mantle-derived magmas.

I-type granites were usually formed by mixing of mantle-derived mafic source and crust-derived felsic magma or dehydration melting of mafic meta-igneous rocks (Huang et al., 2013; Yang et al., 2016; Jiang et al., 2018). Both the “Gingili Grey” and “Pearl Flower” granodiorites are granodiorite rock type with abundant mafic microgranular enclaves (Zhang et al., 2012; Hu, 2019; Yue, 2020; Ju, 2023), and strong evidence such as back veins in the enclaves and variable εHf(t) values in zircons (zircons from “Gingili Grey” has εHf(t) values of −2.5 to 5.3 (Zhang et al., 2012) and −5.1 to 1.3 (Yue, 2020); zircons from “Pearl Flower” has εHf(t) values of −24.1 to −20.8 (Ju, 2023)) can prove the magma mixing process. Additionally, their Nb/U, Nb/Ta, and Nb/Th (Nb/U = 1.6∼6.9, Nb/Ta = 10.3∼14.9, and Nb/Th = 0.4∼1.3) ratios are closer to those from the continental lower crust (Nb/U = 10, Nb/Ta = 11∼12, and Nb/Th = 3), indicating that their granitic magma endmembers are from the lower crust. Thus, we consider that the “Gingili Grey” and “Pearl Flower” granodiorites originated from the mixing of mantle-derived mafic source and lower crust-derived felsic magmas.

The “Cengxi Red”, “Baihujian Red”, “Gingili Grey” and “Pearl Flower” granitoids are located in different places in China, and they also formed in different ages. They theoretically should be under different tectonic backgrounds. As we discussed above, the “Cengxi Red” and “Baihujian Red” are A-type granites, while the “Gingili Grey” and “Pearl Flower” are I-type granites. A-type and I-type granites commonly tend to form in different tectonic environments. In the Y + Nb vs. Rb, Y vs. Nb, Yb + Ta vs. Rb and Ta vs. Rb diagrams (Figure 10), the “Baihujian Red”, “Gingili Grey” and “Pearl Flower” granitoids are plot in the volcanic arc granite field, but the “Cengxi Red” granitoids are plotted in the within plate granite field. However, the “Cengxi Red” and “Baihujian Red” A-type granites mostly plot in the post-collision circle, and they are A₁-type granites, which are related to an intracontinental rift valley or a mantle plume setting. Thus, we consider that they are more likely to have formed in a post-collision extension environment. The “Baihujian Red” granitoids plotted in the volcanic arc field may be affected by the geochemical features of its protoliths in the magma source. Considering the “Gingili Grey” and “Pearl Flower” granodiorites, they belong to I-type granites and plot in the volcanic arc granite field. This is reasonable because I-type granites tend to form in an orogenic belt during subduction processes. We consider that they may probably have been triggered by the subduction of the paleo-Pacific plate.

As I-type granites, the Spanish samples were certainly derived from re-melting of meta-igneous rocks, but their high P contents indicate that they may not have undergone a strong fractional crystallization process (Xiao et al., 2023). Therefore, the relatively high alkaline, P and Rb contents may directly derived from their source regions. Since P has very low solubility under hyperbaric conditions, granites with high P contents tend to have shallow sources (Huang et al., 2013). In addition, Rb and Zr are incompatible elements, which are much more enriched in alkalic rocks than in calc-alkalic rocks (Liu et al., 2019; Xiao et al., 2023). Thus, the Spanish building granites may have protoliths of lower crustal alkalic meta-igneous rocks, most likely alkali basalts.

The Spanish granites in this study were also from different rock bodies, but their similar petrographic characteristics and geochemical compositions, as well as their adjacent locations, indicate that they may be I-type granites generated from a close period in the same tectonic environment. In the R1 vs. R2 diagram, the Spanish samples are plotted in a late orogenic field, similar to the “Cengxi Red”, “Baihujian Red” and “Gingili Grey” granitoids, but different from the “Pearl Flower” granodiorites. It is commonly accepted that A-type granites were generated in late- or post-orogenic and anorogenic periods, but I-type granites can be generated in any environment, such as pre-, syn-, late- or post-orogenic periods (Loiselle and Wones, 1979; Chappell and White, 2015; Xie et al., 2025). The “Cengxi Red” and “Baihujian Red” A-type granites conform to this pattern, while the “Gingili Grey” and “Pearl Flower” I-type granites tend to have different tectonic settings. However, the Spanish building granites are similar to the “Gingili Grey” I-type granites, forming under a late orogenic environment.

The aesthetic characteristics of building granites rely on two main key factors that include specific textural and structural features, as well as the colors reflected. The former are commonly related to crystal sizes and distributions, which are associated with complex magma processes and crystallization history (Badouna et al., 2020). Colors, on the other hand, have a profound effect on the rock’s appearance, strongly depending on its mineral assemblage and chemical composition (Badouna et al., 2020). Comprehensively, the textural and structural features and colors of building granites are macroscopically affected by their genetic types and tectonic backgrounds.

The “Cengxi Red” is syenogranite, which commonly displays a dark-red color, with medium-coarse grained granitic texture, porphyritic-like texture, and massive structure. Since rock-forming minerals in granites are commonly black biotite and hornblende, grey quartz, white plagioclase, and red K-feldspar, the predominant dark-red color of “Cengxi Red” is attributed to the large amount of K-feldspar. Because K-feldspar is the only red-colored rock-forming mineral in granites, the visually dark-red color of the “Cengxi Red” granitoids is largely affected not only by the large-grained K-feldspar phenocrysts but also by the high proportion of K-feldspar in the matrix. However, K-feldspars tend to crystallize in alkaline granites, and alkaline granites are commonly A-type granites formed in extensional environments. Additionally, porphyritic-like texture requires a hypabyssal emplacement. Thus, we consider that the dark-red colored building granites are K-feldspar rich syenogranites, which are commonly A-type granites formed in extensional environments.

The “Baihujian Red” is monzonitic granite, which is commonly light-red in color, with a medium-coarse grained granitic texture and massive structure. The “Baihujian Red” granitoids do not show a porphyritic or porphyritic-like texture, and they contain equal proportions of K-feldspars and plagioclase; this may be the main factor that causes their visually light-red color. Compared to the “Cengxi Red” granitoids, the “Baihujian Red” granitoids contain less K₂O content, which causes a lower proportion of K-feldspar crystallization. The differences in chemical composition may be due to the different protolith or distinct magma evolution process. Moreover, the lack of porphyritic or porphyritic-like textures can indicate a hypogene emplacement of the “Baihujian Red” granitoids. Thus, we consider that the light-red colored building granites are monzonitic granite with equal proportions of K-feldspars and plagioclase, which are also A-type granites formed in extensional environments.

The “Gingili Grey” is granodiorite which usually exhibits a grey color, with a fine-to medium-grained granitic texture and massive structure. The “Gingili Grey” granodiorites also do not have a porphyritic or porphyritic-like texture, indicating a hypogene emplacement, and the visually grey color may possibly be due to its mineral assemblage and particle sizes. The “Gingili Grey” granodiorites are composed of predominately fine-to medium-grained quartz and plagioclase, which are visually grey and white, respectively. However, the black-colored hornblende in it is relatively rare, and the black biotite grains are relatively tiny; this may be the main factor that caused the visually grey color of the “Gingili Grey” granodiorites. Combined with the deductions listed above, we consider that the grey-colored building granites are granodiorites with rare hornblende and tiny biotite grains, which are possibly I-type granites formed in subduction environments.

The “Pearl Flower” is also granodiorite, which is generally black-white colored, with a fine-grained granitic texture and massive structure. Similarly, the absence of porphyritic or porphyritic-like texture can prove that the “Pearl Flower” granodiorites experienced a hypogene emplacement. However, also as granodiorites, the “Pearl Flower” granodiorites show a visually black-white color, which is distinct from the grey-colored “Gingili Grey” granodiorites. This may also be due to the mineral assemblage and particle sizes. The “Pearl Flower” granodiorites also contain fine-to medium-grained quartz and plagioclase, but hornblende and biotite have much larger particles compared to the “Gingili Grey” granodiorites, which results in a darker color index for the “Pearl Flower” granodiorites. Moreover, the “Pearl Flower” granodiorites contain a higher proportion of white plagioclase and a lower proportion of grey quartz compared to the “Gingili Grey” granodiorites, with larger particles of dark-colored minerals, ultimately forming a visually black-white color. Combined with the above deductions, we consider that the black-white colored building granites are granodiorites composed of more plagioclase and less quartz, with larger hornblende and biotite particles, which are probably I-type granites formed in subduction environments as well.

The aesthetic characteristics of Spanish building granites are also controlled by their textural, structural, and most importantly, their colors. When we carefully investigate their petrographic features, we discover that the Spanish samples have a lithology of two-mica granite or muscovite granites: almost all are medium-to coarse-grained, and some of them contain K-feldspar phenocrysts. The colors of these samples are mainly grey, white and pink. Sample AF1 is grey to yellow colored, the grey color is visually controlled by its quartz, and the yellow color is controlled by its biotite. Sample AF2, AF10, BO9, BO2 and PO4 share similar textural, structural and mineral assemblages (Hernández et al., 2024a), but they have visually different colors in pink, white and grey. This may be mainly controlled by their different weathering degrees, because both K-feldspars and plagioclase are light white colored when nearly not altered, while K-feldspars turn pink or red when slightly altered, and both K-feldspars and plagioclase turn into snowy white kaolinite when strongly altered (Liu et al., 2019; Liu et al., 2021). This can be a reasonable explanation that the moderate weathered AF2 and BO2 samples are pink colored, the highly weathered AF10 sample is white colored, and the low weathered BO9 and PO4 samples are grey colored. The rest of the samples, although some of them did not describe colors and weathering degree, also conform to the mentioned patterns, namely, that the yellow colors are controlled by their biotite; while the pink, white or grey colors are controlled by the weathering degree of feldspars therein.