This group is the same as the regular phosphate ion group except that one of the four oxygens is replaced by an hydroxide or OH group. The mineral sainfeldite is similar, but with arsenate as the affected ion group. Color is mostly pink, but also found in shades of gray, yellow, red or brown. Luster is vitreous. Crystals are transparent to translucent.
Cleavage is absent.
Streak is white. Associated Minerals are elbaite , reddingite , rockbridgeite , phosphoferrite and other secondary phosphates. Best Field Indicators are color, locality, associations and crystal habit.