TECHNICAL TERMS USED BY JEWELLERS AND LAPIDARIES. Bezils. - The upper sides and corners (dd) of the Brilliant, lying between the edge of the Table and the Girdle. Cabochon. Collet. -The smooth convex elliptical form used for cutting Precious Garnet, Turquois, Opal, &c. Fig. e, side view. Fig. f, plan. The small horizontal plane, or face (h) at the bottom of the Brilliant. Crown. The upper work of the Rose, which all centres in the work at the top, and is bounded by the horizontal ribs. Facets. Small triangular faces or planes, both in Brilliants and Roses. In Brilliants there are two sorts, Skew- and Skill-facets, and Starfacets. Skill-facets are divided into upper and under. Upper Skill-facets (cc) are wrought on the lower part of the Bezil, and terminate in the Girdle; Under Skill-facets (ff) are wrought on the Pavilions, and terminate in the Girdle. Star-facets (bb) are wrought on the upper part of the Bezil, and terminate in the Table. Girdle. The line (ee) which encompasses the stone, parallel to the horizon; or which determines the greatest horizontal expansion of the stone. Goutte de suif is similar to Cabochon, only the relief is not so great, and, consequently, the form of the stone is flatter. Lozenges are common to Brilliants and Roses. In Brilliants they are formed by the meeting of the Skill-, and Star-facets on the Bezil: in Roses, by the meeting of the Facets in the horizontal Ribs of the Crown. Pavilions are the undersides and corners (gg) of the Brilliants, and lie between the Girdle and the Collet. Ribs. The lines or ridges which distinguish the several parts of the work, both of Brilliants and Roses. Table. The large horizontal planes or faces (a) at the top of the Brilliant. Note. The horizontal line beneath the figures a b, is the distance between the Table and the Collet, or the depth which should be given to a stone of such a size as that in the figure, to insure the greatest amount of lustre. Fig.f. ERRATA AND ADDENDA. Page 1, column 1, line 10 from bottom: for "See GREY OXIDE OF MANGANESE " read "GREY OXIDE OF MANGANESE. See MANGANITE." 9, column 2, line 10 from hottom: for "Bromley "read" Brownley." 10, column 2, bottom line: for " rhomboid" read "rhombohedron." line 13 for 99 10 read 99.10. 12, column 1, line 26 from top: dele "now." line 29: for" with coal and lignite" read" with Brown Coal and Lignite." 14, column 2, line 25 from bottom: for "potash" read "alumina." 21, column 1, line 10 from top: for "Sb" read" Sb." 26, column 2, line 7 from bottom: for "Elæotite" read "Elæolite." 41, column 1. line 26 from bottom: for "Selenite" read " Selenide." 54, column 1, line 15 from top: for "Ca" read "Ċa." 58, column 1: transfer the Analysis of BysSOLITE, and the two following lines, to article on "BURATITE." 64, column 1: transfer the paragraphs headed "Analysis," "Locality," and "Name," from article "CARNALLITE to "CARNAT." 78, column 1, line 24 from bottom: for "Aluminum" read "Aluminium." 79, column 2,, line 32 from top: for "H" read "H 193, column 2, line 22 from bottom: for “TÏ1⁄2” read “Ti Fi.” 195, column 1, line 24 from bottom: for "S" read "S" 197, column 2, line 7 from bottom: after "Dufrénoy" add "A kind of Sparry Iron." 217, column 1, line 5 from top: for “ċ” read "ċa." 220, column 2, line 17 from bottom: for "Alumina" read "Arsenious acid." line 19 from bottom: for "As" read "As." 241, column 2. line 5 from bottom: for "alumina" read "potash." 248, column 2. line 7 from top: for "100" read "1.00." "BRU 252, column 2, line 22 from top: for CITE "read" PERICLASE." 341, column 1, last line: for "NATE" read "NITE." 348, column 2, line 2 from top: for “ Tantalit "read" Tantalite." 389, column 1, line I from top: after A, add "(ferruginous silicate of manganese (Thomson)).' line 3 from top: for "oxide of manganese" read "carbonate of protoxide of manganese (See Dana, vol. ii. p. 189, Analysis 7, from Stirling.)" line 18 from top: after "Locality" add," Stirling, ". A GLOSSARY OF MINERALOGY. ABICHITE. ACHMITE. ACHIRITE, the name given by Werner to Dioptase after Achir Mamed, a Bucharian merchant, who first brought the stone from Siberia, and endeavoured to sell it for Emerald. ACHMATIT, Hermann. A variety of limeand-iron-Epidote, from Achmatowsk. See BUCKLANDITE. ACHMITE, Berzelius, Beudant, Dana, Nicol, Phillips. Oblique primary form an oblique rhombic prism. Isomorphous with Augite. Co lour brownish, or reddish-brown. Opaque; translucent in thin fragments, which exhibit a yellowish-brown tint by transmitted light. Lustre vitreous, inclining to resinous. Streak pale yellowish-grey. Brittle. Fracture imperfect conchoidal. H. 6 to 6·5. S. G. 3.5 to 3.6. ·00 Fig. 1. Fig. 2. 2 ACHRENSTEIN. ADULARIA. BB fuses readily to a black magnetic | Cape Cornwall; Huel Unity, Botallack, Huel globule. Locality. This somewhat rare mineral occurs imbedded in Felspar and Quartz at Rundemyr, near Kongsberg in Norway, in crystals nearly a foot long. They are often macled and bent, and quite fragile. Name. From axun, a point; in allusion to the pointed form of the crystals. G. Rose suggests that Achmite is an altered form of Pyroxene (the Ægirine of Brevig). Brit. Mus., Case 34. ACHRENSTEIN. See BARYTES. α ACHROITE (from a priv. and xóa, colour) the name proposed by Rammelsberg for colourless varieties of Tourmaline. They are found at St. Gotthard, in Elba, and Siberia. ACICULAR ARSENIATE OF COPPER, Allan. See OLIVENITE. Owls, and several other mines. Near the Name. From ȧxTorós, radiated. M. P. G. Horse-shoe Case, 1048 to 1051. ADAMANT, Kirwan: ADAMANTINE SPAR, Phillips: from ∞ priv: and dauów, to subdue. Names given to Corundum from its hardness or from the peculiar lustre which it occasionally displays, resembling that of the AdaACICULAR BISMUTH; or ACICULAR BIS-mant or Diamond. The term AdamantineMUTH-GLANCE, Needle-ore. See AIKENITE. spar is sometimes applied to Sapphire of a ACICULAR-ORE, Jameson. See AIKENITE. hair-brown colour. ACICULAR STONE, Jameson. See SCOLE CITE. ACICULITE, Nicol. See AIKENITE. ADELPHOLITE, Nordenskiöld. A niobate or tantalate of iron and manganese, with 9.7 per cent of water. Colour brownish-yellow ACIDE ARSENIEUX, Beudant. See AR- to brown and black. Subtranslucent. Lustre SENOLITE. ACMITE. See ACHMITE. ACORITE, Dufrénoy. See AZORITE. ACTINOLITE, Dana, Nicol; ACTINOTE; ACTYNOLITE, Phillips, Jameson, comprehends the glassy and fibrous varieties of Hornblende, and has been subdivided into glassy, asbestiform, and granular. Glassy Actinolite includes the bright-green bladed crystals or columnar forms, with a vitreous or pearly lustre. The crystals are long slender prisms, which are easily broken. The fibrous crystallizations of a green or greenishgrey colour, disposed in wedge-shaped masses or in radii, sometimes promiscuously aggregated, are often termed asbestiform Actinolite. Granular Actinolite includes such grassgreen varieties as have a granular composition. The green colour is owing to a small quantity of iron and chromium. Comp. Mgs Si2+(ċa, Fe, Mn,) Si. greasy. Streak white or yellowish-white. H. 35 to 45. S.G. 3.8. Locality. Rajamaki in Tamela, Finland. ADIAPHANE SPAR, Mohs. See GEHLENITE and NEPHRITE. A ADINOLE, Beudant. See PETROSILEX. ADULAIRE, La Metherie; ADULAR, Werner, Haidinger; ADULARIA, Jameson. transparent or translucent variety of potashFelspar (Orthoclase), found in granitic rocks. It occurs both massive and crystallized in forms which are sometimes extremely complicated. Colour commonly greenish-white,, greyish, or milk-white. Frequently iridescent. Lustre vitreous inclining, to pearly on the faces of perfect cleavage. Brittle. Fracture uneven to conchoidal. H. 6. S.G. 2.575. Analysis by Abich, from St. Gotthard: Peroxide of iron Analysis by Bonsdorff, from Taberg: Potash Silica 59.75 Lime 0.76 102.12 Localities.-English. Cornwall; the Lizard; the Cheesewring; Cadgwith Point; Localities.-English. Tintagel, Cornwall; in slate.- Welsh. Snowdon; with Quartz. -Scotch. Island of Arran, Buteshire. Irish. Slieve Corra, Mourne Mountains, co. Down.-Foreign. St. Gotthard in Switzerland, and particularly on one of the |