Sterrett, D. B. (1913) Gems and precious stones, _in_ Mineral resources of the United States, Calendar Year 1912, Part II, Non-metals: U. S. Geol. Survey, pp. 1023-1060. Plate I [Illustration: A Gem-quality celestite crystals from Travis County, Texas. Twice natural size. Lower portion of the crystals is colorless; the tips are dark blue.] [Illustration: B Opalized wood from the Texas Gulf Coastal Plain. Specimen at left is rich brown and tan; specimen at right is fossil palm wood and is black, reddish brown, and white. One-third natural size.] Plate II [Illustration: A Gem-quality garnet crystals and faceted gem from Gillespie County, Texas. Natural size.] [Illustration: B Labradorite from Brewster County, Texas. Both stones are pale yellow. One and a half times natural size.] Plate III [Illustration: A Pink microcline crystal from Burnet County, Texas.] [Illustration: B Smoky quartz from Burnet County, Texas. Natural size. Colorless crystal at center back is included for color comparison.] Plate IV [Illustration: Polished agate from gravels of the Rio Grande near Zapata, Zapata County, Texas. Bands are blue and gray; other inclusions are brown, yellow, and reddish. One and a half times natural size.] Plate V [Illustration: A Texas tektites (bediasites) showing variety of surface features. Natural size.] [Illustration: B Topaz crystal from a pegmatite dike near Streeter, Mason County, Texas. Natural size. Measurements: 1½ by 1⅝ by 3 inches; weight: 194 grams (970 carats); pale blue; mostly gem quality.] Plate VI [Illustration: A Topaz from stream gravels near Streeter, Mason County, Texas. Natural size. Left to right: colorless worn pebble; emerald-cut pale-blue topaz, weight 10 carats; pale-blue worn pebble, weight 205 carats; step out sky-blue topaz, weight 13 carats; pale-blue worn pebble.] [Illustration: B Tourmaline crystals in schist from Llano County, Texas.] Index A actinolite: 26 agate: 20, 28, 38 agatized wood: 27 allanite: 21 almandite: 22 amazonite: 23 amazon stone: 23 amber: 18 amethyst: 25 Amethyst Hill: 25 amorphous gemstones: 9 andalusite: 30 Arkansas: 19 Armstrong County: 21 augite: 18, 28