Actinolite
Actinolite is a known member of the Calcic Clino-Amphibole Subgroup of the Amphibole Group of minerals that includes Actinolite, Ferro-edenite, Kaersutite, Pargasite, Richterite and Tremolite. The Amphibole Group is a comprehensive and team that is complex of currently split into several sub-groups. Actinolite and Tremolite have almost the chemical that is same but differ in the quantities of iron and magnesium. Iron is reasonably abscent in Tremolite. Actinolite is rarely facetable and gems that are faceted usually tiny since crystals are generally very fibrous. A sizable (over 1 carat), clean, faceted Actinolite treasure is very rare. Actinolite ranges in color from pale to very dark green, even black and seldom dark orangish brown. It occurs as green needle inclusions in quartz significantly more usually than a treasure by itself.
There are many localities for Actinolite. In Austria, on Mt. Greiner, Zillertal, and at Untersulzbachtal. From Zermatt, Valais, Switzerland. At Snarum and Arendal, Norway. From the Ural Mountains, Russia. In the USA, from Gouverneur, St. Lawrence County, brand new York; Franklin and Newton, Sussex County, New Jersey; Chester, Windsor County, Vermont; within the Fairfax quarry, Centreville, Fairfax County, Virginia; Crestmore, Riverside County, California; at Salida, Chaffee County, Colorado. “Nephrite jade” occurs in america, south and east of Lander, Fremont County, Wyoming; north from Cape San Martin, Monterey County, California; and around Jade Mountain, near the Kobuk River, Alaska. Along the Fraser River, British Columbia, Canada. Around Mt. Cook, South Island, Brand New Zealand. Fine material from the Kunlun Mountains, Sinkiang Uighur Autonomous Region, Asia.
| Chemical Formula: | Ca2(Mg,Fe)5Si8O22(OH)2 |
| Calcium Magnesium Iron Silicate Hydroxide | |
| Molecular Weight: | 853.16 gm |
| Composition: | Sodium | 0.59 % | Na | 0.80 % | Na2O |
| Calcium | 8.60 % | Ca | 12.03 % | CaO | |
| Magnesium | 9.71 % | Mg | 16.11 % | MgO | |
| Titanium | 0.11 % | Ti | 0.19 % | TiO2 | |
| Manganese | 0.13 % | Mn | 0.17 % | MnO | |
| Aluminum | 1.39 % | Al | 2.63 % | Al2O3 | |
| Iron | 8.58 % | Fe | 10.61 % | FeO / 0.47 % Fe2O3 | |
| Silicon | 25.64 % | Si | 54.86 % | SiO2 | |
| Hydrogen | 0.24 % | H | 2.11 % | H2O | |
| Oxygen | 45.01 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | As bladed crystals, to 15 cm; columnar, may be kinked or bent; radiating fibrous to asbestiform; granular to massive. |
| Twinning: | Simple or lamellar |
| Cleavage: | [110] Distinct/Good |
| Fracture: | Splintery to Granular |
| Tenacity: | Brittle |
| Moh’s Hardness: | 5.5 – 6.0 |
| Density: | 3.03 – 3.24 (g/cm3) |
| Luminescence: | Non-fluorescent |
| Lustre: | Vitreous,Silky |
| Radioactivity: | Not Radioactive |
| Color: | Bright green to grayish green; rarely orange to orangish brown. |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous (sometimes dull) |
| Refractive Index: | 1.619 – 1.644 Biaxial ( – ) |
| Birefringence: | 0.022 – 0.026 |
| Dispersion: | Weak |
| Pleochroism: | Weak |
