When sharpening a high quality knife, you need a material harder than the steel in the knife. That's why we have offered both diamond steel and ceramic sharpening rods. They both work well, but they both have their drawbacks. Diamond steel puts a razor sharp edge on very quickly, but the steel can have a shorter lifespan because the expensive synthetic diamond material is merely adhered to the surface of the rod and can erode over time, especially, if you use too much pressure when sharpening. A ceramic rod can last forever, but you sacrifice the hardness of the diamond steel and consequently, it can take longer to achieve peak results. As is often the case, out of the contradiction of opposites, a new synthesis is born. Ruby is the second hardest material on the planet. Through innovative 'powder metallurgy', a corundum (mineral in ruby) tube 1/8th of an inch thick is sintered to the rod.
To translate the tech lingo for you- in the case of sharpening rods, it turns out 'Rubies are Forever.' The result takes the best of both ceramic and diamond steel- a tool that will give you an elite edge for a lifetime