N natural glass: 18, 24, 28 Needle Peak, Presidio County: 27 nivenite: 21 Nolan County: 19 Nueces River: 25 O obsidian: 24, 29 Oklahoma: 29 opal: 20, 24 opalized wood: 35 orbicular jasper: 28 ounce: 7 P Packsaddle Mountain: 23 Packsaddle schist: 30 palm wood: 21, 35 Palo Duro Canyon: 21 pavilion: 13, 16 facets: 16 girdle facets: 16, 17 pearl: 24-25 pegmatites and/or pegmatite dikes: 18, 20, 21, 22, 23, 26, 29, 39 petrified wood: 26 phantom crystals: 26 pistacite: 20 pleochroism: 5 point: 7 polishing: 17 lap: 13, 16 preformed stone: 16 preforming: 15 Presidio County: 20, 22, 24, 25, 26, 27, 28 properties of gemstones: 5-7 Q quartz: 20, 21, 23, 25-28, 29, 30 smoky: 38 R radioactive elements: 22 radioactivity of gadolinite: 21 rarity: 6 Reeves County: 26, 27 Rio Grande: 25 gravels of: 21, 27, 38 Valley: 27 rock crystal: 26 rose quartz: 26 S Sabine River: 25 sanding: 12 sanidine: 28 sawing: 10 scheelite: 20 schorl: 30 size: 7 “skill” facets: 16 “slab” of gem materials: 11 Smithsonian Institution: 21 smoky quartz: 23, 26, 37 smoky topaz: 29 Spanish topaz: 29 specific gravity: 7 spinel: 18, 28 star facets: 17 step cut: 15 streak: 6 synthetic gems: 7 T table facet: 13, 15 tektite (bediasite): 28-29, 39 tenacity: 6 thorogummite: 21 topaz: 23, 26, 29-30, 39, 40 quartz: 29 tourmaline: 26, 29, 30-31, 40 Town Mountain, Llano County: 26, 30 transparency: 6 Travis County: 19, 35 Trinity River: 25 tumbled gems: 17 turquoise: 31 U U. S. National Museum: 30 V value of gemstones: 6, 7 Val Verde County: 24 valverdites: 24 Van Horn, Hudspeth County: 27 W Walker County: 29 Washington County: 20 Webb County: 21 weight, units of: 7, 25 Z Zapata County: 38 Transcriber’s Notes --Silently corrected a few typos. --Renumbered figures 6 and 7 (and references to them) to correspond to their order in the printed book. --Retained publication information from the printed edition: this eBook is public-domain in the country of publication. --In the text versions only, text in italics is delimited by _underscores_. End of the Project Gutenberg EBook of Texas Gemstones, by Elbert A. King, Jr.