The Navigator handle is G-10. As far as GIN-I goes, I'll let Sal's words from an earlier thread do the talking:
"GIN-I (Gingami I, means sliver paper in Japanese) has been around longer than either ATS. Specifically a knife steel, it was the primary steel that Spyderco used since the first Clipits in 1981. Most of our knives were made with it. It is an excellent steel. It seems to be more reistant to chipping than either of the ATS versions, better in corrosion resistance, not a good in edgeholding as the ATS versions."
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Dave
Let no one ever from henceforth say one word in any way countenancing war. It is dangerous even to speak of how here and there the individual may gain some hardship of soul by it. For war is hell, and those who institute it are criminals. Siegfried Loraine Sassoon