In this study, we investigated the optical, magnetic, and electrical transport properties of Si1-xMnx(0.1 < x < 0.9) single crystals grown by the vertical Bridgman method. The alloys with a Mn concentration of up to 64% demonstrated weak ferromagnetic ordering around T-C = 30 K. The Si0.25Mn0.75 and Si0.18Mn0.82 alloys showed weak ferromagnetic ordering at 70 K and antiferromagnetic ordering at 104 K, as confirmed by magnetization, neutron diffraction, and transport studies.