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$C:\Documents and Settings\Alan Smithee\My Documents\MOTM$ @oqhk1/01Lhmdq`knesgdLnmsg9@rsqnogxkkhsd The month we are shining the spotlight on astrophyllite, a rare, complex silicate from one of the world’s most remarkable mineralogical provinces—the Kola Peninsula of northern Russia. Read on to learn about astrophyllite’s unusual colors, luster, and attractive starburst patterns, as well as the preparation that goes into our write-ups. OVERVIEW PHYSICAL PROPERTIES Chemistry: (K,Na)3(Fe,Mn)7Ti2Si8O24(O,OH)7 Basic Potassium Sodium Iron Manganese Titanium Oxysilicate, often containing small amounts of fluorine, calcium, magnesium, aluminum, niobium, and zirconium. Class: Silicates Subclass: Single-chain Inosilicates Group: Astrophyllite Crystal System: Triclinic Crystal Habits: Usually as small, thin, tabular or bladed crystals grouped in radiating, starburst-shaped aggregates; also disseminated, lamellar, and massive. Color: Usually golden-yellow, bronze-yellow, yellowish-brown, or amber; less frequently brown, greenish- brown, or reddish-brown. Colors can be patchy or zoned. Crystals are often pleochroic, exhibiting shifts in color with changes in viewing angle. Luster: Sub-metallic, pearly on cleavage surfaces Transparency: Usually translucent to opaque; thin crystals may be transparent. Streak: Golden to yellowish-brown Cleavage: Perfect in one direction Fracture: Uneven; brittle. Hardness: 3.0-3.5 Specific Gravity: 3.3-3.4 Luminescence: None Refractive Index: 1.680-1.700 Distinctive Features and Tests: Best field marks are yellow-to-brownish colors, color zoning, and pleochroism; perfect cleavage in one direction; brittleness; radiating, starburst-shaped crystal aggregates; sub-metallic luster; and occurrence in syenite and nepheline-syenite fissures and pegmatites. Can be confused with augite, which is harder and forms shorter prisms; and schorl, which is harder and forms hexagonal crystals. Astrophyllite is slightly soluble in acids and fuses into a dark, glassy, slightly magnetic material. Dana Classification Number: 69.1.1.1 NAME The name “astrophyllite,” pronounced as-TROH-fih-lite, is derived from three Greek words: astron, or “star,” phyllon, meaning “leaf” or “sheet,” and lithos, meaning “stone”, alluding to its starburst-shaped, radiating patterns of thin, flat crystals–“Star-Leaf-Stone.” Astrophyllite was originally known as “brown mica.” The obsolete spellings of “aastrophyllite,” “asterophyllite,” and “astrofillite” persist in some literature. In European mineralogical literature, astrophyllite appears as Aastrophylit and astrophyllita. COMPOSITION: Astrophyllite is a member of the silicates, the largest of all mineral classes, in which silicon and oxygen combine with one or more metals. It is classified as a single-chain inosilicate, an important group of rock-forming minerals also known as pyroxenes that consist of single chains of silica tetrahedra. Astrophyllite crystallizes in the triclinic system, which is characterized by three axes of different lengths, none of which are perpendicular to the others. Many chemically complex minerals such as Bnoxqhfgs 1/01 ax Qhbg`qc % Bgdqxk Rhsshmfdq L hmdq`k ne sgd L nmsg Bkt a 06 6 / N qu hkkd @ u dmt d B`l aqh`+ B@ 8 2 3 17 0,7 //,8 3 0,4 4 8 3 v v v -l hmdq`knesgdl nmsgbkt a-nqf 1 @oqhk1/01Lhmdq`knesgdLnmsg9@rsqnogxkkhsd astrophyllite crystallize in the triclinic system. Astrophyllite’s substantial density (specific gravity 3.3-3.4) is due to close atomic packing and to the relatively heavy, essential metals iron, manganese, and titanium, which together account for one-third of its molecular weight. As an idiochromatic (self-colored) mineral, astrophyllite’s characteristic colors are caused primarily by iron and to a lesser extent by manganese, together with the nature of its crystal lattice. Astrophyllite is a rare mineral that occurs in cavities, fissures, and pegmatites of feldspar-rich, silica-poor, igneous rocks, usually syenite and nepheline syenite. Astrophyllite also occurs occasionally in certain volcanic environments. COLLECTING LOCALITIES: The finest astrophyllite specimens come from the Khibiny, Lovozero, and Keivy massifs on Russia’s Kola Peninsula. Astrophyllite is also collected in Norway, Brazil, Chile, Canada, Greenland, China, Malawi, Namibia, Morocco, South Africa, and Pakistan. Sources in the United States are located in Arkansas, Colorado, Maine, Montana, New Hampshire, Rhode Island, Washington, and Wisconsin. We have never seen astrophyllite at shows from any location other than Kola. HISTORY, LORE, & GEMSTONE/TECHNOLOGICAL USES: Astrophyllite was first identified in 1844, when it was known as “brown mica.” Researchers confirmed its complex chemistry and recognized it as a new mineral species in 1854. Mineralogists defined its atomic structure using X-ray diffraction methods in 1927. Astrophyllite was thought to be a single mineral until the 1950s, when advanced analytical techniques enabled mineralogists to differentiate a series of chemically and structurally similar minerals. By the 1970s, they had identified eight closely-related minerals that, along with astrophyllite, now make up the astrophyllite group. Because of its rarity and softness, astrophyllite has very limited use in jewelry. Radiating patterns of astrophyllite that contrast with light-colored matrix material are occasionally cut and polished into beads and cabochons, the latter mounted in silver pendant settings. Mineral collectors value astrophyllite for its rarity, unusual chemical composition, and attractive, starburst-shaped, radiating crystal patterns. Large specimens with well-developed, starburst patterns make very unusual display pieces. Apart from serving as the mineralogical model for its own laboratory synthesis, astrophyllite has no technological uses. Modern metaphysical practitioners believe that astrophyllite enhances confidence, intellect, and insight, and assists one in reaching his or her full potential by creating an awareness that limitations and obstacles can be overcome. ABOUT OUR SPECIMENS: Our specimens were collected at a classic astrophyllite locality—the Khibiny Massif on the Kola Peninsula in Murmanskaya Oblast’ in the Northern Region of Russia. Located in Russia’s far northwest and part of Lapland, the Kola Peninsula is one of the world’s richest and most diverse mineralogical provinces. The Khibiny Massif, a horseshoe-shaped plateau with elevations reaching 3,900 feet, is a highland in the central part of the Kola Peninsula. Geologically, the Khibiny Massif originated some 360 million years ago when a large mass of alkaline magma intruded granite-gneiss country rock. This intrusion, about 20 miles in diameter, consists largely of nepheline syenite, a rock similar to granite but with less silica and higher levels of alkali and alkali-earth metals. After undergoing several complex metamorphic phases, the thoroughly fractured Khibiny Massif was subjected to a process of hydrothermal reflux, in which hot or superheated water circulated through faults and fissures, dissolving and transporting many minerals. With changes in temperature, pressure, and levels of acidity (or alkalinity), these solutions then redeposited their dissolved mineral content in the form of many unusual minerals. Our astrophyllite specimens were collected by Russian kyanite and rare-earth miners who supplement their incomes by selling specimens to mineral dealers from St. Petersburg and Moscow. 10 YEARS AGO IN OUR CLUB: Eudialyte, Kipawa, Temiscaminque County, Quebec, Canada. Another mineral with a hard-to-pronounce name found in nepheline-syenite! Beautiful specimens of eudialyte also come from Kola, though our pieces from Canada were a lovely pinkish-red color. There is very little eudialyte from either place on the market now, which is why we buy all we can afford when we do see it! Bnoxqhfgs 1/01 ax Qhbg`qc % Bgdqxk Rhsshmfdq L hmdq`k ne sgd L nmsg Bkt a 06 6 / N qu hkkd @ u dmt d B`l aqh`+ B@ 8 2 3 17 0,7 //,8 3 0,4 4 8 3 v v v -l hmdq`knesgdl nmsgbkt a-nqf 2 @oqhk1/01Lhmdq`knesgdLnmsg9@rsqnogxkkhsd COMPREHENSIVE WRITE-UP COMPOSITION We are happy to be featuring astrophyllite now for the second time, the first being in July 2001, when it was first coming on the market in quantity from Kola. Now it is much less available and much more valuable. Other minerals we have featured from this mineral-rich peninsula are staurolite, featured in May 2000 and in May 2010; the unusual calcite pseudomorph after ikaite known as glendonite, in September 2003; kyanite, in October 2004; the ruby variety of corundum, in December 2006; and “Rainbow Pyrite” in July 2007. The mention of each of these names brings back wonderful memories! The latter two minerals are still available as part of the sets of twelve minerals we have going back to 2005 in Gold-level size, and the last four can be found in Silver-level size sets, which are available from 2002 on. Astrophyllite, chemical formula (K,Na)3(Fe,Mn)7Ti2Si8O24(O,OH)7, contains the elements potassium (K), sodium (Na), iron (Fe), manganese (Mn), titanium (Ti), silicon (Si), oxygen (O), and hydrogen (H). Astrophyllite’s ideal molecular weight consists of 6.37 percent potassium, 2.08 percent sodium, 23.05 percent iron, 4.56 percent manganese, 7.73 percent titanium, 17.73 percent silicon, 38.16 percent oxygen, and 0.32 percent hydrogen. Astrophyllite is a member of the silicates, the largest of all mineral classes, in which silicon and oxygen combine with one or more metals. The basic structural unit of all silicate minerals is the silica tetrahedron 4- (SiO4) , in which a silicon ion is surrounded by

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