TL;DR: NEA Water is a main entry in the 外星矿物知识引擎 database.
Carbonaceous asteroids contain water bound in phyllosilicate minerals. OSIRIS-REx and Hayabusa2 confirmed water-bearing minerals. While extraction requires more energy than lunar ice mining, some NEAs are energetically easier to reach than the lunar surface.
Location
C-type near-Earth asteroids (Bennu, Ryugu-type)
Estimated Quantity
5-10% water by mass in hydrated minerals
Extraction Method
Thermal dehydration of phyllosilicates at 300-800°C
Economic Value
Comparable to lunar water if accessible