 | | Book |
| museum quality but many minerals can be found on mine dumps or can be purchased or traded. After introducing...black rock, containing no quartz but rich in the feldspar minerals pyroxene and olivine. Old basalts with...rocks contain large crystals, often of the feldspar group and are known as porphyries. The individual...traprock is diabase in which lath-like crystals of feldspar grow first and darker minerals grow round them...structure. It contains mostly quartz and orthoclase feldspar with some smaller amounts of a darker mineral |
 | | Journal (issue) |
| greatly with the sophisticated techniques used to mine the first bulk sample pit. Virtually all o f the...gemologist, is associate director of the Los Angeles County Museum of Natural History, Los Angeles, CA; and...most sophisticated equipment available was used to mine the gravels for bulk sampling at Banjar Baru. The...Kalimantan at this time. Local inhabitants continue to mine by traditional methods in the area of Ngabang, following...an additional two 36-ft3 buclzet-line dredges to mine the deeper Cempalza paleochannel at an annual production |
 | | Book (edition) |
| text most used by an increasingly large and active group of gemstone collectors who are fascinated by the... CRYSTAL STRUCTURES AND PROPERTIES types. A group of atoms held together by bonds in such a way form...sodium may amounts! In such cases it member of a group of about eight minerals with essentially the same...important groups of gem found on page 241. The group concept of relating similar gem species has been...many mountain ranges. Coarse tex- of potassium feldspar, quartz, plus parency) are extremely rare over |
 | | Journal (article/letter/editorial) |
| . . . . . . . . . . . . . . . . . . . Platinum group elements (PGE) . . . . . . . . . . . . . . . . ...platinum-group-element deposits . . . . . . . . . . . . 6.3. Structure-related platinum-group-element...Sedimentary platinum-group-element deposits . . . . . . . . . . 6.5. Platinum-group-element supply and.... . . . . . . . . . . . . . . . . . . . . . . Feldspar . . . . . . . . . . . . . . . . . . . . . . ....and mineralogy of feldspar . . . . . . . . . . . . . . . . 39.2. Magmatic feldspar deposits . . . . |
| | Journal (article/letter/editorial) |
| . . . . . . . . . . . . . . . . . . . Platinum group elements (PGE) . . . . . . . . . . . . . . . . ...platinum-group-element deposits . . . . . . . . . . . . 6.3. Structure-related platinum-group-element...Sedimentary platinum-group-element deposits . . . . . . . . . . 6.5. Platinum-group-element supply and.... . . . . . . . . . . . . . . . . . . . . . . Feldspar . . . . . . . . . . . . . . . . . . . . . . ....and mineralogy of feldspar . . . . . . . . . . . . . . . . 39.2. Magmatic feldspar deposits . . . . |
 | | Book (edition) |
| bonds are generally weaker than these bond types. A group of atoms held together by bonds insucha way as to...minerals. Diopside, for example, is a member of a group of about 8 minerals with essentially the same structure...groups of gem minerals is found on page 141. The group concept of relating similar gem species has been...ranges. Coarse texture, composed of potassium feldspar, quartz, plus some mica or hornblende and accessory...contains plagioclase feldspar, little quartz, some biotite. Granodiorite—like feldspar. diorite, but |
| | Book (edition) |
| bonds are generally weaker than these bond types. A group of atoms held together by bonds in such a way as...minerals. Diopside, for example, is a member of a group of about 8 minerals with essentially the same structure...groups of gem minerals is found on page 141. The group concept of relating similar gem species has been...quartz grains. Arkose-sandstone composed chiefly of feldspar and quartz grains. Graywacke-dense, dark-colored...ranges. Coarse texture, composed of potassium feldspar, quartz, plus some mica or hornblende and accessory |
 | | 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...1995: 582). Madawaska [Faraday] mine near Bow Lake, Hastings County. Some of the world's finest ilmenite |
 | Gaines, Richard V., Skinner, H. Catherine W., Foord, Eugene E., Mason, Brian, Rosenzweig, Abraham, King, Vandall T. (1997) Dana's New Mineralogy (8th ed.) Wiley-Interscience. p.1872 | Book (edition) |
| Species containing more than one anion or anion group may be assigned to a separate class or may be assigned...specifies the atomic (cation to anion, or to anion group) ratio for the mineral. This and the remaining numbers...appropriate Dana number. When recognized, membership in a group is noted. Occasionally, the phrase “an inadequately...internally contradictory. 5A. Groups The term group refers to an aggregate or multiple (usually three...identical or closely similar structure and chemistry. A group may be named when there are several end members |
