Graftonite
Graftonite is a phosphate that is mainly found in complex granitic pegmatites and often found connected with Triphylite. Its color is a salmon-pink to reddish brown to dark brown when altered. It is not a gem that is particularly attractive mostly one for collectors of rare and unusual gems.
Distribution: In the United States Of America, on Melvin Mountain (Type Locality), about eight km west of Grafton, during the Palermo no. 1 and Rice mines, near North Groton, Grafton County, at the Parker Mountain quarry, Center Strafford, Strafford County, and many other places in New Hampshire; through the Waisenen quarry, Greenwood, Oxford County, Maine; into the Bull Moose mine, five km southeast of Custer, Custer County, as well as the Nickel Plate mine, 1.5 km south of Keystone, Pennington County, South Dakota. From near São Luiz do Paraitinga, São Paulo, and the Énio pegmatite mine, northeast of Galiléia, Minas Gerais, Brazil. During the Ranquel and Cacique Canchuleta mines, San Luis, Argentina. From Sidi Bou Othmane, Morocco. In the Valle Della Madonna, Brissago, Tessin, Switzerland. At Olgiasca, Lake Como, Lombardy, Italy. From Hagendorf, Bavaria, Germany. Within the Kondakov region, eastern Siberia, Russia. Extra localities continue steadily to be recognized.
| Category: | Phosphate minerals |
| Chemical Formula: | (Fe2+,Mn2+,Ca)3(PO4)2 |
| Iron Manganese Phosphate | |
| Molecular Weight: | 351.93 gm |
| Composition: | Calcium | 3.42 % | Ca | 4.78 % | CaO |
| Manganese | 14.05 % | Mn | 18.14 % | MnO | |
| Iron | 28.56 % | Fe | 36.75 % | FeO | |
| Phosphorus | 17.60 % | P | 40.33 % | P2O5 | |
| Oxygen | 36.37 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | Very rare crude crystals, stout prismatic; usually massive, cleavable, in laminated intergrowths with Triphylite, to 0.5 m. |
| Twinning: | None |
| Cleavage: | Good on {010}, Fair on {100} |
| Fracture: | Irregular/Uneven to Subconchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 5.0 |
| Density: | 3.67 – 3.79 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Other: | Readily soluble in acids. |
| Color: | Salmon-pink to reddish brown, dark brown when altered; nearly colorless in transmitted light. |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous towards Resinous |
| Refractive Index: | 1.695 – 1.736 Biaxial ( + ) |
| Birefringence: | 0.024 – 0.027 |
| Dispersion: | Relatively weak; r > v or r < v |
| Pleochroism: | Faint; X = Y = colorless; Z = pink |
