The diamond/diamond crystal form of Group B type placer deposits in eastern Australia is elongated or flat irregular and regular dodecahedron, with few green and brown spots on the surface (Davies et al., 1999, 2002); A small amount of diamonds/diamonds in the Kalimantan placer mines are very eye-catching bright amber color, and some diamonds/diamonds show a unique "Diver's Helmet" morphology, with obvious lack of broken or cracked crystals, and wear related to transportation. The characteristic diamond/diamond ratio is very low (Smith et al., 2009); the Ural Mountains contain more transparent green crusted diamond/diamond than other placer mining areas, and the crystal form is mainly flat dodecahedron (Laiginhas, 2008 ); the surface color spots of placer diamonds/diamonds in Myanmar and Thailand are mainly brown, and green spots are rare (Win et al., 2001; Griffin et al., 2001).

Figure 8.52 The morphology of diamonds from Kalimantan Island, Indonesia (b is the special "Diver's Helmet" morphology)

(According to Smith et al., 2009)

Figure 8.52 Morphology of diamond from Kalimantan, Indonesia (b, the special Diver's Helmet appearance)

(Smith et al., 2009)

Figure 8.53 Kalimantan Island, Indonesia Internal structure characteristics of diamond

(According to Smith et al., 2009)

Figure 8.53 Internal structure of diamond from Kalimantan, Indonesia

(Smith et al. , 2009)

Table 8.14 Comparison of diamond origin characteristics of major alluvial deposits all over the world

According to Davies et al ., 1999, 2003; Sobolev, 1984; Smith et al., 2009; Stachel et al., 2000a; 2000b, 2002; Cartigny et al., 2004; Harris et al., 2004; Win et al., 2001; Griffin et al., 2001; Bluck et al., 2005; Khachatryan & Kaminsky, 2003; Laiginhas, 2008; Yang Mingxing et al., 2001; Ma Wenyun, 1989; Guo Jiugao, 1989; Yang Mingxing, 2000 Literature review