The Apatite Group of Minerals
The Apatite Group minerals are a group of phosphates, arsenates and vanadates that have very similar hexagonal or pseudohexagonal monoclinic structures.
This group includes several important and colorful minerals such as
apatite
(from where this group gets its name),
mimetite,
pyromorphite and
vanadinite; all pictured above.
Apatite is a general name for three official minerals named chlorapatite, fluorapatite and hydroxylapatite.
The general formula for the group is A5(BO4)3
(OH, F, Cl).
The A cations can be any of several metal ions such as calcium, barium, sodium, lead, strontium, lanthanum and/or cerium.
The B cations can be either phosphorous, vanadium or arsenic.
Carbonate anion groups, CO3, and silicate anion groups, SiO4,
can substitute to a limited extent for the
BO4 groups.
These are the minerals of the Apatite Group:
- Alforsite (Barium Phosphate Fluoride Hydroxide)
- Apatite (Calcium Phosphate Chloride Fluoride Hydroxide)
- Belovite-(Ce) (Strontium Sodium Cerium Lanthanum Phosphate Fluoride Hydroxide)
- Belovite-(La) (Strontium Sodium Lanthanum Cerium Phosphate Fluoride Hydroxide)
- Carboniatefluorapatite (Calcium Carbonate Phosphate Fluoride)
- Carboniatehydroxylapatite (Calcium Carbonate Phosphate Fluoride)
- Chlorapatite (Calcium Phosphate Chloride)
- Clinomimetite (Lead Arsenate Chloride)
- Fermorite (Calcium Strontium Arsenate Phosphate Hydroxide)
- Fluorapatite (Calcium Phosphate Fluoride)
- Hedyphane (Lead Calcium Arsenate Chloride)
- Hydroxylapatite (Calcium Phosphate Hydroxide)
- Johnbaumite (Calcium Arsenate Hydroxide)
- Mimetite (Lead Arsenate Chloride)
- Morelandite (Barium Calcium Lead Arsenate Phosphate Chloride)
- Pyromorphite (Lead Phosphate Chloride)
- Stontiumapatite (Strontium Calcium Phosphate Hydroxide Fluoride)
- Svabite (Calcium Arsenate Fluoride)
- Turneaureite (Calcium Arsenate Phosphate Chloride)
- Vanadinite (Lead Vanadate Chloride)
The
silicate minerals
britholite-(Ce),
britholite-(Y),
chlorellestadite,
fluorellestadite,
hydroxylellestadite and
mattheddleite and the
sulfate mineral
cesanite
are isostructural with this group, but are generally not considered apart of the Apatite Group.