Editorial Feature

Caresite - Occurrence, Properties, and Distribution

May 28 2014

Caresite is a member of the quintinite group of minerals. The mineral was first discovered in 1997 in Poudrette quarry, Mont Saint-Hilaire in Rouville County, Quebec, as well as in the Corporation quarry, Montreal in Quebec, Canada.

It was named after Steve Cares and Janet Cares of Sudbury, MA, Canada, who found the mineral.

Properties of Caresite

The following are the key properties of Caresite:

Cell Data
- Space Group: C1 or C1
- a = 9.48(5)
- b = 6.98(3)
- c = 9.30(5)
- α = 91.14(10)°
- β = 104.85(10)°
- γ = 90.0(10)°
- Z = 4

Crystal Data
- Triclinic, pseudomonoclinic
- Point Group: 1 or 1
- As radiating tufts and bundles of crystals, to 2mm; crystals elongated || [101] and flattened on {001}. Forms observed are {100} and {001}, also (110)
- Twinning: Always, by rotation about [101]
- X-ray Powder Pattern: 3.48 (100), 4.56 (70), 3.69 (60), 2.852 (40), 1.460 (40), 2.277 (30), 2.242 (30)

Chemical Composition

Elements	Content 1	Content 2
F	52.1	51.52
Ca	29.86	31.05
Al	10.27	10.45
H₂O	7	6.98
Total	99.23	100

Optical Properties
- Optical Class: Biaxial (+)
- Orientation: X ≃ b; Z ^ c = 10(5)°
- α = 1.411(2)
- β = 1.416(2)
- γ = 1.422(2)
- 2V(meas.) = 77(2)°
- 2V(calc.) = 78°

Estimated Properties

Electron density	Bulk density (electron density) = 2.58 g/cm³ note: Specific gravity of Caresite = 2.58 g/cm³
Photoelectric	PE_Caresite = 11.27 barns/electron U = PE_Caresite x ρ Electron density = 29.11 barns/cm³
Fermion index	Fermion index = 0.008 Boson index = 0.99
Radioactivity	Caresite is not radioactive

How to Identify Caresite

Caresite is either colorless, or it occurs in an orange-brown or yellow color. It exhibits transparent appearance, perfect cleavage, vitreous luster, and white streak. It has brittle fractures, as displayed by glasses and most non-metallic minerals. It can be formed as tabular structures or prismatic crystals.

The average density of caresite is 2.58 g/cm³, and its hardness is 2.