HIC

HIC is not a steel, but stands for High-Impact Ceramic. It is first used by Spyderco as a blade material, in the MT 40 MT Mule Team knife.

From Spyderco's website:

High-Impact Ceramic (HIC)—a state-of-the-art Ceramic Injection Molding (CIM) material. Developed by Harcane Industries of Switzerland, this remarkable zirconia-based material is significantly more resistant to breakage than conventional ceramics. It is specially formulated to obtain the highest density during sintering, giving it exceptional toughness and resistance to crack propagation. This proprietary material also achieves far greater hardness than steel blades, allowing it to both cut and retain its edge incredibly well.