 | | Journal (article/letter/editorial) | | of Earth, which is not recorded directly in the rock record, is termed the Hadean Eon; Volume 76, September/Octokr...northeasterly-trending continentul Figure 2. Geologic map of the Colorado Front Range showing the Precambrian metamorphic...Karistrom 1978; Lanthier 1978). Farther south in Colorado, sediments accumulated in decper-water rocks formed...Survey into “Early, Middle, and Late” Eras. In Colorado we because of the subsequent folding and overthrusting...subduction zone and possibly the creation Era in Colorado and Wyoming of a volcanic island arc. Carpenter |  | | Journal (article/letter/editorial) | | inch on edge, from the Henderson mine, Clear Creek County. Figure 2 (right). Green fluorite encrusted with...Mountain Wilderness area near Columbine Lake, La Plata County; largest crystal measures 1.25 inches on edge;... FLUORITE BARBARA L. MUNTYAN Ouray County Museum Ouray, Colorado 81427 Mineral photographs by John R...locations in Mexico; in Elmwood, Smith County, Tennessee, and in Hardin County, Illinois, in the United States;...eastern Russia. It also occurs in many localities in Colorado, where it is found in colors ranging from pale |  | | Report (issue) | | Denver, Colorado, USA © 2011 by Lithographie, LLC P.O. Box 11613 • Denver, CO 80211 • USA Phone 1.303...collection Robert Weldon photo Above: Topaz, 5.5 cm tall El Chalten, Santa Cruz, Argentina Scott Rudolph collection...Topaz ALFREDO PETROV & JOHN RAKOVAN 34. Colorful Colorado DAVID W. BUNK 42. Mongolian Topaz: The Gorkhi...surface (001), the refractive index of a given specimen can provide a sensitive method for determining...Mine, Thomas Range, Utah; Utah Mineral and Fossil specimen, Scovil photo Middle left: Topaz and quartz, 2 |  | | Journal (article/letter/editorial) | | COLORADO TOPAZ Topaz, Al Si0 (F,OH) is one of Colorado's better known gem minerals. Though Col orado...(PJM), 975 (TCM) Box 25046, Federal Center Denver, Colorado 80225-0046 A ccording to Cross and Hillebrand...discovery of Colorado topaz was made about 1880 by a Mr. Thiebald,* "a prospector of Colorado Springs."...area. The largest fine-quality topaz specimens in Colorado occur in several separate and distinct localities...are also referred to the general discussions of Colorado topaz in Eckel (1961) and Pearl (1963) and to |  | | Journal (article/letter/editorial) | | Although Colorado may be most noted for rhodochrosite or amazonite, the many varieties and associations...a k e w o o d , Colorado 80225 DIANNE L. K I L E 333 S a l e m Street Aurora, Colorado 80011 C O L O...and J. A. Mur phy for an update to Minerals of Colorado: A 100-Year Record (Eckel, 1961). 374 ROCKS... Quartz was a familiar gemstone to many early Colorado residents, as documented by an extensive body...body of literature. The first published list of Colorado mineral localities (in cluding quartz) was included |  | | Journal (issue) | | R. Kampf Natural History Museum of Los Angeles County George Robinson National Museums of Canada Arthur...SPECIMENS from the collection of the Geology Museum, Colorado School of Mines. See page 242 for a full description... All rights reserved. notes fromthej EDITOR COLORADO-III Here we are with our third special issue devoted...devoted to the mines and minerals of Colorado. As most long-time subscribers know, the first in the series...about $200 on the out-of-print market. The second Colorado issue was vol. 10, number 6 (1979), and we still |  | | Journal (issue) | | Menzies Pink topaz from the Thomas Range, Juab County, U ta h .........................................to Uli c/o Martin Zinn, P.O. Box 2433, Evergree Colorado 80439. I The Mineralogical Record, volume 26,... Crawford, David Minerals Crystal Systems D & M Rock & Gem D J Minerals, Inc. De Trin Minerals Delta...Carter Fine Minerals Richards - Foster Rock & Mineral Magazine Rock Art Fossils of The UK - England Rocks...Thom pson, Wayne A., Fine Minerals Tideswell Dale Rock Shop - England Tintic & Tiger Trading Co. Top M |  | | Journal (article/letter/editorial) | | claim, Pikes Peak batholith, Teller County. The Collector’s Edge specimen, Jeff Scovil photo. PETER J. MODRESKI...Mail Stop 150, Box 25046 Federal Center Denver, Colorado 80225 pmodreski@usgs.gov C olorado is, of course...been written as guides to mineral collecting in Colorado. A classic, which went through three major editions...1951 version with a slightly different title), is Colorado Gem Trails and Mineral Guide, by Pearl (1951,...up-to-date guidebook to the state’s minerals is Colorado Rockhounding, by Voynick (1994). Other published |  | | Journal (issue) | | on Amazonite 7.5 cm, from the Smoky Hawk claim, Colorado. Collected by the Dorris family; Tom Spann photo...thrill of discovery. After all, every mineral specimen in collections around the world has but a single...‘bruised’ area in the center which resulted from the specimen falling on my hard hat as it was being pried off...off the back. “The most memorable specimen that I collected was one at the very top of the dome, and...came in, one at a time, to see this magnificent specimen before we removed it. “By afternoon, we left the |  | | Book | | only a small number — some 40-50 — are generally rock-forming, e.g. quartz, felspar, mica, pyroxene, amphibole...of various rocks, and in consequence are called rock-building minerals. System of Mineral Classification...largest part of the gases and vapour escapes through rock fissures and cracks to the surface of the earth...weather- ing are gradual, irrevocable and continuous. Rock surfaces are mechanically affected by changing temperature...Biological processes can also produce changes in rock surfaces. The effects of weathering can cause profound | | | Book | | only a small number — some 40-50 — are generally rock-forming, e.g. quartz, felspar, mica, pyroxene, amphi...of various rocks, and in consequence are called rock-building minerals. System of Mineral Classification...largest part of the gases and vapour escapes through rock fissures and cracks to the surface of the earth...weather ing are gradual, irrevocable and continuous. Rock surfaces arc mechanically affected by changing temperature...Biological processes can also produce changes in rock surfaces. The effects of weathering can cause profound |  | | Book | | long (Marty, 2004 ). AFRICA widely in Litchfield County, where good crystals were taken from quartz veins...region (Brunet, I 977b ). NEW YORK Amity, Orange County. At many isolated collected sites between the towns...Litchfield County. Ilmenite masses and crystals from somewhere near Washington, Litchfield County, were described...Lake Road occurrence, Faraday Township, Hastings County. In fall 1994, Dan and Shelley Lambert extracted...Madawaska [Faraday] mine near Bow Lake, Hastings County. Some of the world's finest ilmenite specimens |  | | Book | | HfiRIN COUNTY FREE LIBRfiRY 311110G386652Q I V Russell P MacFal A COLOR TREASUF FOR COLLECTORS...to Hunting Locations ? i 9 GIVEN TO THE MARIN COUNTY LIBRARY BY MARI N L MTNF.RAT. SOCTETY DAVID...the sociologists to decide Not everyone takes up rock hunting because of an interest in mineralogy There...comes when, after hours of hammering, a resistant rock splits just the way you want it to. And in the end...Keep Your Eyes Open PLACES TO SEARCH Active Mines Rock Masses 3 Aid the for for Experts and Ouarnes |  | | Book | | of a thin section of the minerals comprising the rock mass. To do this successfully requires a knowledge...Descriptions of fiftyeight of the most common of the rock-making minerals are given, special attention being...classification and description of the more important igneous rock cussed briefly. types. Following Iddings, Winchell...of Petrographic Methods," Luquer's "Minerals in Rock Sections," Rogers's "Study of Minerals," Findlay's...and Biaxial; ; CHAPTER DESCRIPTION OF IMPORTANT ROCK- 5. 69 MAKING MINERALS Isometric Minerals. CHAPTER |  | | Report (issue) | | .......................11 The Ledge (Charlotte County Granite) quarry.........................................................................63 Split Rock, Marble Cove mines......................................................................136 Black Rock occurrence ...........................................................................181 Admiral Rock quarries........................................................................197 viii Black Rock mine........................................... |  | | Book | | Middle European » Jurassic. blation. The removal of rock debris by wind action. boral. » Echinodermata (Echinoids)...(Echinoids) and Fig. 44. rasion. Reduction in size of rock particles by mechanical wearingway, especially by...equivalent. “te Accessory minerals. Minerals present in a rock in such small amounts that their presence or absence...cicular (mineralogy). Needle-like. eid rock. An igneous rock with 10% or more free quartz. The term arises...were regarded as salts these acids. If therefore a rock contained excess silica, it was 15 regarded as |  | | Book | | hornfels, 290 Section through tourmaline-corundum rock deposit in 9.17 Perak, sketch 380 Photomicrographs...5.1 a2 53 ok 7.2 Time correlation of the major rock formations of the Malay Peninsula, 8.3 10 Evidence...English Equivalent Malay (Bahasa Malaysia) Batu Rock or milestone Besar Batang Large Main river Hill...stream A method of extracting ore from weathered rock Lampan by bringing a stream of water to it and...concentrating the ore without lifting the containing rock Pekan Town Pulau Sungei Island (or Sungai) River |
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