Smithsonian Nature Guide Rocks and Minerals
DK Publishing
Language: English
Pages: 354
ISBN: 2:00234521
Format: PDF / Kindle (mobi) / ePub
The new DK Nature Guides form a comprehensive, accessible, and informative series of illustrated reference books that tackle key natural history subjects in DK's uniquely visual style. Produced in collaboration with expert consultants at the Smithsonian Institution, each guide is expertly written and will give you knowledge of the natural world at your fingertips.
From blue schist to blue granite, malachite to meteorites, and taconite to travertine, Nature Guide Rocks and Minerals is packed full of stunning images that reveal intricate details and unique characteristics of each rock and mineral.
Using close-up photographs of every specimen and profiles containing examples from all over the world, Nature Guide Rocks and Minerals brings revealing key facets and details perfect for quick identification.
luster of cerussite crystals is particularly bright. A widespread secondary mineral that occurs in the oxidation zones of lead veins, cerussite is formed by the Collector’s gem Faceted cerussite action of carbonated water on other stones, such as this lead minerals, particularly galena and rare gem, are brilliant anglesite (p.132). but too soft to be worn. MINERALS | CARBONATES 120 PROFILE Large crystals In this specimen of azurite, large, well-formed crystals rest on a goethite matrix.
The chromate minerals all contain a CrO4 group, the molybdates an MoO4 group, and the tungstates a WO4 group. sulfur atom chromium atom oxygen atom oxygen atom SULFATE CHROMATE molybdenum atom tungsten atom oxygen atom oxygen atom MOLYBDATE TUNGSTATE Crystal structure Tetrahedra are the structural basis of the sulfates, chromates, tungstates, and molybdates. The central metal atom gives each group its name. Barite crystals This large group of tabular barite crystals is from the Wet
MINERALS | SULFATES 135 PROFILE Orthorhombic 4 m n o p q Celestine crystals This superbly crystallized specimen of blue celestine crystals is from Madagascar. The largest crystal is more than 1 1⁄2 in (3.5 cm) long. 3–3 1⁄2 4.0 Perfect vitreous luster Uneven White large, tabular crystal blue coloration Vitreous, pearly on cleavage small celestine crystals granular celestine VARIANTS r SrSO 4 CELESTINE Colorless celestine Prismatic, colorless crystals on a sulfur matrix Single
highly prized as an ornamental stone. Anorthoclase is widespread, but fine examples come from Cripple Creek, Colorado, USA; Larvik, Norway; and Fife, Scotland. MINERALS | SILICATES: FELDSPARS 177 twinned, tabular crystal PROFILE Triclinic 4 6–6 ⁄ m 2.6 n Perfect, good to o Conchoidal uneven, brittle 1 2 p White q Vitreous to pearly vitreous to pearly luster Tabular albite This specimen consists of a large group of tabular, white albite crystals, many of which are twinned. r NaAlSi O
also have major and minor prism faces with edges parallel to each other. In most crystals, some faces are more developed than others. pyramid faces prism face Naming crystal faces The names of crystal faces and their relationship to the c axis are shown here. The predominant crystal face gives the crystal its habit name. c axis pyramid face long prismatic habit pinacoid face prism face pyramid face dipyramidal habit Prismatic topaz Although this topaz crystal exhibits prismatic, pryamidal,