Comparison between the geometric albedo derived by the stellar occultation (p_V*, Shevchenko & Tedesco 2006; Lupishko 2018) and the polarimetric, photometric, and spectral properties associated with the low albedo asteroids with hydration features. Blue cross markers indicate asteroids with ${\widehat{R}}_{0.7}+\sigma {\widehat{R}}_{0.7}<1$ (i.e., Ch-type asteroids, DeMeo et al. 2009), while black circles indicate dark asteroids other than Ch-type ones. (g) Square markers indicate the asteroids whose ${\widehat{R}}_{2.7}$ were obtained from Takir & Emery (2012); Takir et al. (2015).