Appendix:Dictionary of Mining, Mineral, and Related Terms/Z/1

z-coordinate
 * One of the three coordinates in a three-dimensional rectangular coordinate system.

z-direction
 * One of three orthogonal optic directions in biaxial crystals. Light with its electric vector (vibration direction in early terminology) parallel to the z-direction has the highest refractive index (n (sub gamma ) ) for a given crystal and is called the slow ray. In orthorhombic crystals, the z-direction is constrained by symmetry to correspond to one of the crystallographic directions, the correspondence determined empirically. In monoclinic crystals, one optic direction, commonly the y-direction, is constrained by symmetry to correspond to the unique diad. In triclinic crystals, there is no symmetrical constraint relating optic directions to crystallographic axes.

zeasite
 * Wood opal, formerly a name for fire opal.

zebra dolomite
 * A term used in the Leadville district of Colorado for an altered dolomite rock that shows conspicuous banding (generally parallel to bedding) consisting of light-gray coarsely textured layers alternating with darker finely textured layers. See also: zebra rock.

zebra rock
 * a. A term used in the Colville district of NE Washington State for a dolomite that shows narrow banding consisting of black layers (indicative of organic matter) alternating with white, slightly coarse-grained, and somewhat vuggy layers. See also: zebra dolomite.

b. A term used in Western Australia for a banded quartzose rock of Cambrian age.

Zeiss konimeter
 * A portable dust-sampling instrument. See also: konimeter.

Zellweger furnace
 * A long-hearth reverberatory furnace used at Iola, KS.

Zemorrian
 * Lower Lower Miocene.

zeolite
 * A generic term for class of hydrated silicates of aluminum and either sodium or calcium or both, of the type Na (sub 2) O.Al (sub 2) O (sub 3) .nSiO (sub 2) .xH (sub 2) O . The term originally described a group of naturally occurring minerals. The natural zeolites are analcite, chabazite, heulandite, natrolite, stilbite, and thomsonite. Artificial zeolites are made in a variety of forms, ranging from gelatinous to porous and sandlike, and are used as gas adsorbents and drying agents as well as water softeners. Both natural and artificial zeolites are used extensively for water softening. The term zeolite now includes such diverse groups of compounds as sulfonated organics or basic resins, which act in a similar manner to effect either cation or anion exchange.

zeolite mimetics
 * The dachiardite group of zeolites.

zeolite process
 * a. A base exchange method of treating hard water, in which zeolites, contained in a tank, remove salts. The zeolite layer is regenerated by backflushing with brine.

b. See: base exchange.

zeolitic deposit
 * A deposit, particularly of native copper, that occurs in basalt accompanied by minerals of the zeolite group.

zeolitization
 * Introduction of, alteration to, or replacement by, a mineral or minerals of the zeolite group. This process occurs chiefly in rocks containing calcic feldspars or feldspathoids, and is sometimes associated with copper mineralization.

zeophyllite
 * A triclinic mineral, Ca (sub 4) Si (sub 3) O (sub 8) (OH,F) (sub 4) .2H (sub 2) O ; pseudohexagonal; forms white spherical, radiated folia; at Cross-Preisen, Bohemia, Czech Republic.

zero air voids curve
 * The curve showing the zero air voids unit weight as a function of water content. Syn: saturation curve.

zero air voids unit weight
 * The weight of solids per unit volume of a saturated soil mass. See also: unit weight.

zero-length spring
 * Special type of gravimeter spring for which the length is proportional to the applied force.

zero-point energy
 * The kinetic energy remaining in a substance at a temperature of absolute zero.

zero potential
 * The actual potential at the surface of the Earth taken as a point of reference.

zero time
 * When conducting a mine ventilation pressure survey, zero time is the time of the commencement of the survey from the base station, and the reading of the control barometer there is taken as the pressure datum to which subsequent pressures are referred.

zero-zero gel
 * A condition wherein a drilling fluid fails to form measurable gels during a quiescent 10-min time interval.

zeta potential
 * The potential difference across an electric double layer, usually between a solid surface and a liquid. Syn: electrokinetic potential See also: surface.

zeta-potential layer
 * The zone of shear surrounding a particle immersed in an electrolyte.

zeunerite
 * A tetragonal mineral, Cu(UO (sub 2) ) (sub 2) (AsO (sub 4) ) (sub 2) .10H (sub 2) O ; autunite group.

zeylanite
 * See: ceylonite.

zhemchuzhnikovite
 * A trigonal mineral, NaMg(Al,Fe)(C (sub 2) O (sub 4) ).8H (sub 2) O ; an oxalate occurring in green crystals that appear violet in artificial light; in veinlets in coal in the Chaitumusuk deposits, Siberia, Russia.

Ziervogel process
 * The extraction of silver from sulfide ores or matte by roasting in such a way as to form sulfate of silver, leaching this out with hot water, and precipitating the silver by means of metallic copper.

zietrisikite
 * Incorrect spelling of pietricikite, a waxlike hydrocarbon similar to ozokerite.

zigzag car loader
 * A form of vertical chute in which the chute is divided into independent sections that can be raised or lowered on a track arrangement. It is flexible and can be lowered to the bottom of the car, giving a solid stream of coal from loading pocket to car.

zigzag fold
 * See: chevron fold.

zigzag rule
 * A wooden rule (generally 2 m or 6 ft long, folded zigzag fashion in 15-cm or 6-in lengths), used by drillers, craftsmen, etc., to measure short distances. The rule usually is graduated in centimeters or in feet, inches, and fractions of an inch (sometimes in feet, tenths of a foot, and hundredths of a foot).

zigzag transformer
 * A zigzag transformer is a transformer intended primarily to provide a neutral point for grounding purposes. Syn: grounding transformer.

ziment water
 * Water impregnated with copper; found in copper mines.

Zimmermann's rule
 * A graphical method for finding the lost part of a vein on the other side of a fault.

zinc
 * a. The native metallic element, Zn.

b. A bluish-white, lustrous metal. Employed to form numerous alloys with other metals including brass, nickel silver, commercial bronze, spring brass, soft solder, and aluminum solder. Used extensively by the automotive, electrical, and hardware industries.

zincaluminite
 * A light-blue mineral, Zn (sub 6) Al (sub 6) (SO (sub 4) ) (sub 2) (OH) (sub 26) .5H (sub 2) O.

zinc blende
 * See: sphalerite.

zinc bloom
 * See: hydrozincite; zinc oxide.

zinc box
 * Wooden or enamel-ware rectangular box, with a bottom grid that supports zinc shavings. Used in the cyanide process to precipitate dissolved gold from a pregnant solution. Its place was taken by use of zinc dust. See also: Merrill-Crowe Process.

zinc carbonate
 * White; ZnCO (sub 3) ; soluble in acids, in alkalies, and in ammonium salt solutions; insoluble in water; and dissociates losing carbon dioxide at 300 degrees C. Used in ceramics and as a pigment. Also used less accurately to refer to any of several basic carbonates of zinc, which include the zinc-ore mineral hydrozincite, Zn (sub 5) (CO (sub 3) ) (sub 2) (OH) (sub 6) or Zn (sub 5) (OH) (sub 6) (CO (sub 3) ) (sub 2) and synthetically prepared pigments of the same or similar composition. Syn: smithsonite; calamine; zinc spar.

zinc chloride
 * White; hexagonal; ZnCl (sub 2) ; poisonous. Obtained by the solution of zinc, or zinc oxide, in hydrochloric acid, or by burning zinc in chlorine. Used in galvanizing iron, as a catalyst, as a dehydrating agent, as a condensing agent, as a wood preservative, as an ingredient in soldering fluxes, in burnishing and polishing compounds for steel, in electroplating, in glass-etching compositions, in petroleum refining, and in pigments.

zinc chromate
 * ZnCrO (sub 4) ; a golden-yellow pigment. Of variable composition; the chemically pure zinc chromate, a yellow crystalline powder is said to be zinc chromate heptahydrate, ZnCrO (sub 4) .7H (sub 2) O . Called zinc yellow, but this term is also applied to hydrated zinc chromate and to hydrated zinc-potassium chromate. Another zinc chromate is dark green to black and has a different composition; isometric. ZnCr (sub 2) O (sub 4) . Syn: zinc chrome; zinc yellow.

zinc chrome
 * See: zinc chromate; zinc yellow.

zinc dust
 * Finely divided zinc that usually contains small amounts of zinc oxide and impurities. Also called powdered zinc; zinc gray.

zinc gray
 * See: zinc dust.

zinc hydrosulfite
 * White; amorphous; ZnS (sub 2) O (sub 4) ; and soluble in water. Used as a depressant in flotation.

zincite
 * A red to yellow brittle mineral; (Zn,Mn)O. It is an ore of zinc, as in New Jersey where it is associated with franklinite and willemite. Syn: red zinc ore; red zinc oxide; ruby zinc; spartalite.

zinckenite
 * See: zinkenite.

zinckiferous
 * Carrying zinc.

zinc-magnesia chalcanthite
 * A variant of chalcanthite with the formula, (Cu,Zn,Mg)SO (sub 4) .5H (sub 2) O.

zinc melanterite
 * A member of the monoclinic melanterite group, in which iron is partially replaced by zinc.

zinc-melanterite
 * A monoclinic mineral, (Zn,Cu,Fe)SO (sub 4) .7H (sub 2) O.

zinc minerals
 * The principal ore is sphalerite, ZnS ; other important ore minerals are smithsonite, ZnCO (sub 3) ; hemimorphite, Zn (sub 4) Si (sub 2) O (sub 7) (OH) (sub 2) .H (sub 2) O ; franklinite, (Zn,Mn,Fe)(Mn,Fe) (sub 2) O (sub 4) ; willemite, Zn (sub 2) SiO (sub 4) ; and zincite, ZnO.

zinc oxide
 * White or yellowish-white; white turns yellow on heating; ZnO; odorless; absorbs carbon dioxide from the air; used in pigments, ceramic glazes, and opaque glass and in the manufacture of magnetic ferrites and specialized ceramics. Zinc oxide is a common constituent in high-grade fluoride opal glass, in tank-window glass, and in some optical glass. Commonly used in dry-process, cast-iron enamels. Syn: zincite; zinc bloom; zinc white.

zincrosasite
 * A monoclinic mineral, (Zn,Cu)(CO (sub 3) )(OH) (sub 2) ; rosasite group; at Tsumeb, Namibia.

zinc scum
 * The zinc-silver alloy skimmed from the surface of the bath in the process of desilverization of lead by zinc.

zincsilite
 * A monoclinic mineral, Zn (sub 3) Si (sub 4) O (sub 10) (OH) (sub 2) .4H (sub 2) O(?) ; smectite group; in Batystau, Kazakhstan.

zinc spar
 * See: smithsonite; zinc carbonate.

zinc spinel
 * See: gahnite.

zinc sulfate
 * Orthorhombic ZnSO (sub 4) ; used in flotation.

zinc sulfate heptahydrate
 * Colorless; needles; ZnSO (sub 4) .7H (sub 2) O ; odorless; astringent, metallic taste; effloresces in air; sp gr, 1.9661; melting point, 50 degrees C if heated rapidly; soluble in water and in glycerol; insoluble in alcohol; and its solutions are acid to litmus. Used in preparing zinc chemicals. Orthorhombic; molecular weight, 287.54; sp gr, 1.957 (at 25 degrees C, referred to water at 4 degrees C) and ranges from 1.9 to 2.1; Mohs hardness, 2.0 to 2.5; melting point, 100 degrees C; loses 7H (sub 2) O on heating to 280 degrees C; and slightly soluble in alcohol and in glycerol. Occurs as the mineral goslarite, which is white or yellowish; formed by the oxidation of sphalerite (ZnS) in damp locations, esp. in the presence of iron sulfides.

zinc sulfide
 * a. Alpha zinc sulfide is the hexagonal mineral wurtzite. See also: alpha zinc sulfide; wurtzite.

b. Beta zinc sulfide is the isometric mineral sphalerite. See also: beta zinc sulfide.

zinc sulfide monhydrate
 * Colorless, white, or yellowish; crystalline; ZnSO (sub 4) .H (sub 2) O ; molecular weight, 115.45; sp gr, 3.98; melting point, 1,049 degrees C; insoluble in water; and soluble in acids. Used as a pigment and in white glass and in opaque glass.

zinc vitriol
 * See: goslarite.

zinc white
 * Used as a pigment. It is the whitest of all pigments; permanent, not poisonous, but lacks the opacity and covering power of white lead or titanium dioxide. See also: zinc oxide.

zinc yellow
 * A greenish-yellow pigment. See also: zinc chromate. Syn: zinc chrome.

zinkazurite
 * A mineral found in small, blue crystals; probably a mixture of sulfate of zinc and carbonate of copper.

zinkenite
 * A hexagonal mineral, Pb (sub 9) Sb (sub 22) S (sub 42) ; in steel-gray crystals or exceptionally thin folia in fibrous masses. Also spelled zinckenite. Syn: keeleyite.

zinkite
 * See: zincite.

zinkosite
 * Orthorhombic ZnSO (sub 4).

zinn
 * Native tin. Syn: gediegen. See also: tin.

zinnwaldite
 * A monoclinic mineral, KLiFeAl(AlSi (sub 3) )O (sub 10) (F,OH) (sub 2) ; mica group; basal cleavage; pale violet, yellowish or grayish brown; in granites, pegmatites, and greisens.

zippeite
 * An orthorhombic mineral, K (sub 4) (UO (sub 2) ) (sub 6) (SO (sub 4) ) (sub 3) (OH) (sub 10) .4H (sub 2) O ; radioactive; orange-yellow to bright yellow; an alteration product of uraninite occurring with gypsum, uranopilite, and limonite. Formerly called dauberite.

Zipper
 * Trade term for a conveyor belt lacing or fastening appliance, which can be applied to any thickness and width of belt. A lever mechanism is used to supply the pressure. The appliance is totally enclosed and grease-filled to protect against dust and damage.

zircon
 * A tetragonal mineral, ZrSiO (sub 4) ; occurs widely in granite, granite pegmatite, other felsic igneous rocks, and placers; the chief source of zirconium; a refractory; if cut and polished, the colorless varieties provide exceptionally brilliant gemstones. Syn: azorite; zirconite; hyacinth; jacinth.

zircon flour
 * Finely milled zircon sand.

zircon group
 * Zircon, along with rutile, ilmenite, and monazite, constitutes a group of heavy minerals that are usually considered together because of their occurrence as black sands in natural beach and dune concentrations. For marketing, complete separation of the rutile and zircon as high-grade products is necessary. Separation is effected by combinations of electromagnetic and electrostatic processes, together with gravity concentration.

zirconia brick
 * Brick containing zirconium oxide; used in metallurgical furnaces.

zirconiferous
 * a. Containing zircon or yielding zircon.

b. Containing zirconium or yielding zirconium.

zirconite
 * A gray or brownish variety of zircon.

zirconium
 * A grayish-white lustrous metallic element. Symbol, Zr. Occurs widely, but only in combined form, esp. in the minerals zircon, (ZrSiO (sub 4) ), and baddeleyite, (ZrO (sub 2) ). Uses include resisting corrosion, as a structural material in nuclear reactors, as an alloying agent, deoxidizer, bonding agent, refractory material, and in low-temperature superconductive magnets.

zirconium minerals
 * Principal ore minerals are zircon and baddeleyite. Main uses are as refractories, ceramics, opacifiers, abrasives, enamels, insulators, and alloys. They are also a source of hafnium. Transparent zircon is a gemstone.

zirconium phosphate
 * Normal zirconium phosphate, ZrP (sub 2) O (sub 7), has a reversible inversion at 300 degrees C and at 1,550 degrees C dissociates into zirconyl phosphate, (ZrO) (sub 2) P (sub 2) O (sub 7) , with loss of P (sub 2) O (sub 5) as vapor. Zirconyl phosphate is stable up to about 1,600 degrees C and has a very low thermal expansion--1 x 10 (super -6) (20 to 1,000 degrees C).

zirconium silicate
 * ZrSiO (sub 4), natural silicate of zirconium found in Brazil and elsewhere. One such deposit known as brazilite is said to contain about 80% zirconium oxide in a semimanufactured form. This product is employed as a refractory in the making of "zirkite" bricks and cement. In rare cases, used as a cobalt groundcoat constituent. Zirconium silicate is used in formulation of zircon enamels that depend upon crystallization of zircon compounds for opacity development. See also: zircon sand.

zirconium-vanadium blue
 * A pigment for use in ceramic glazes. The composition is (parts by weight): ArO (sub 2), 60% to 70%; SiO (sub 2) , 26% to 36%; V (sub 2) O (sub 5) , 3% to 5%. Alkali must also be present; e.g., 0.5% to 5% Na (sub 2) O. In the absence of alkali, a green color is produced. Syn: vanadium-zirconium turquoise.

zirconolite
 * A discredited syn. of zirkelite.

zircon sand
 * a. A very refractory mineral, composed chiefly of zirconium silicate, having low thermal expansion and high thermal conductivity.

b. A natural zircon-bearing material found in Australia, India, and Florida. See also: zirconium silicate.

zirkelite
 * a. A monoclinic mineral, (Ca,Th,Ce)Zr(Ti,Nb) (sub 2) O (sub 7) ; pseudocubic; dimorphous with calciobetafite of the pyrochlore group; radioactive; occurs in pyroxenite and alluvial deposits.

b. An obsolete name for altered basaltic glass.

Zirkite
 * A trade name for a mixture of zircon and baddeleyite.

zirklerite
 * A trigonal mineral, (Fe,Mg) (sub 9) Al (sub 4) Cl (sub 18) (OH) (sub 12) .14H (sub 2) O ; massive fine granular; at Hanover, Germany.

zoisite
 * An orthorhombic mineral, CaAl (sub 3) (SiO (sub 4) ) (sub 3) (OH)] ; epidote group; dimorphous with clinozoisite; vitreous or pearly; varicolored; a common rock-forming mineral in medium-grade metamorphic rocks. The rose-red variety has been called thulite.

zonal axis
 * See: zone axis.

zonal structure
 * A term used esp. in miscroscopic work to describe those minerals whose cross sections show their successive concentric layers of growth.

zonal theory
 * A theory of hypogene mineral-deposit formation, and the spatial distribution patterns of mineral sequences to be expected from change in a mineral-bearing fluid as it migrates away from a magmatic source. It also deals with thermal-chemical gradients associated with the genesis of ore deposits, whether of direct magmatic origin or not, and with metallogenic zoning on a regional scale.

zone
 * a. A belt, band, or strip of earth materials, however disposed; characterized as distinct from surrounding parts by some particular property or content; e.g., zone of saturation, fault zone, or a zone of secondary enrichment. CF: belt.

b. See: aureole. c. A minor interval in any category of stratigraphic classification. There are many kinds of zones, depending on the characteristics under consideration--biozones, lithozones, chronozones, mineralized zones, metamorphic zones, zones of reversed magnetic polarity, etc. The term should always be preceded by a modifier indicating the kind of zone to which reference is made. d. A metal zone is equivalent to a mineral zone, yet the terms mineral and metal are not synonymous. e. The ground or mass bounded by horizontal or inclined planes or curved surfaces in which given chemical or physical conditions exist, such as zone of saturation or zone of weathering. f. A group of beds characterized by the presence of one or more specific fossils; e.g., zonal fossil or fossils. g. Geologically, a distinctively mineralized area, region, or level. In a specific lode or other deposit, the progressive change from upper to lower horizons. At the top is outcrop or gossan, oxidized or weathered. Next is the leached zone, impoverished by dissolution of its values (or part of them), which may be redeposited below in the zone of secondary enrichment. Below this is the primary, or unaltered zone, which consists of the original sulfide formation. h. An area or region more or less clearly set off or characterized as distinct from surrounding or adjoining parts; e.g., the mineral zone in a metalliferous region. i. A series of faces of a crystal whose intersection lines with each other are all parallel. j. See: zones.

zone axis
 * That crystallographic direction through the center of a crystal which is parallel to the intersection edges of the crystal faces defining the "crystal zone." Syn: crystal axis; zonal axis.

zone melting
 * Highly localized melting, usually by induction heating, of a small volume of an otherwise solid piece. By moving the induction coil along the rod, the melted zone can be transferred from one end to the other. In a binary mixture where there is a large difference in composition on the liquidus and solidus lines, high purity can be attained by concentrating one of the constituents in the liquid as it moves along a rod.

zone of accumulation
 * See: B-horizon.

zone of aeration
 * A subsurface zone containing water under pressure less than that of the atmosphere, including water held by capillarity, and containing air or gases generally under atmospheric pressure. This zone is limited above by the land surface and below by the water table. It contains vadose water. CF: zone of capillarity.

zone of capillarity
 * A subsurface zone that overlies the zone of saturation in which capillary voids hold water above the zone of saturation by molecular attraction acting against gravity. CF: zone of aeration.

zone of cementation
 * The layer of the Earth's crust below the zone of weathering in which percolating waters cement unconsolidated deposits by the deposition of dissolved minerals from above.

zone of discharge
 * A term suggested for that part of the zone of saturation having a means of horizontal escape.

zone of enrichment
 * See: zone of secondary enrichment.

zone of faces
 * All faces, belonging to one or more forms, the normals to which lie in one plane (the zone plane) and whose edges of intersection are parallel to the zone axis. See also: zone axis.

zone of flow
 * See: zone of plastic flow.

zone of fracture
 * a. The outer, rigid part of a glacier, in which the ice is much fractured.

b. The upper, brittle part of the Earth's crust in which deformation is by fracture rather than by plastic flow; that region of the crust in which fissures can exist. CF: zone of plastic flow. Syn: zone of rock fracture.

zone of illuviation
 * See: B-horizon.

zone of influence
 * The zone of rock surrounding an excavation, in which the additional stresses caused by the excavation are above a certain arbitrary value, is termed the zone of influence.

zone of mobility
 * See: asthenosphere.

zone of oxidation
 * See: oxidized zone.

zone of plastic flow
 * That part of the Earth's crust that is under sufficient pressure to prevent fracturing, i.e., is ductile, so that deformation is by flow. CF: zone of fracture. Syn: zone of flow; zone of rock flowage.

zone of rock flowage
 * See: zone of plastic flow.

zone of rock fracture
 * The upper part of the lithosphere in which rocks are under stresses less than the stresses required to close their interstices by deformation of the walls of the interstices.

zone of saturation
 * A subsurface zone in which all the interstices are filled with water under pressure greater than that of the atmosphere. This zone is separated from the zone of aeration (above) by the water table. Syn: saturated zone; phreatic zone.

zone of secondary enrichment
 * The zone in which supergene enrichment has taken place.

zone of substantial deformation
 * See: destressed area.

zone of weathering
 * The superficial layer of the Earth's crust above the water table that is subjected to the destructive agents of the atmosphere and in which soils develop. CF: zone of cementation.

zone refining
 * A purification technique in which a molten or high-temperature zone is moved along a length of material to be purified to bring about impurity segregation; the impurities become concentrated in the slowly moving hot zone, leaving behind the cooler solidified material that has a higher purity than the original material. The technique depends on differences in composition of liquids and solids in equilibrium and may be repeated to attain high degrees of purity. It usually is applied to crystalline materials, such as germanium or silicon.

zones
 * In a shaft furnace, the different portions (horizontal sections) are called zones, and are characterized according to the reactions that take place in them, as the zone of fusion or smelting zone, the reduction zone, etc.

zones of lode
 * A lode may be divided into three main zones: (1) unaltered ore at depth; (2) gossan or altered surface portion of the lode, which contain native metals, oxides, and oxysalts that result from weathering of the ore; and (3) secondary enrichment which lies between the first two zones, where interaction between waters from the gossan and the unaltered ore have produced new materials, often of considerable economic value.

zone time
 * Standard time applied at sea in which the surface of the globe is divided into 24 zones of 15 degrees, or of 1 h, each. The "0 zone" extends 7.5 degrees east and west of the meridian of Greenwich (England), (the Prime Meridian); the zones are designated by the number of hours that must be applied to the local time to obtain Greenwich time. Abbrev., ZT.

zoning
 * a. In ore deposits, the spatial distribution patterns of elements, minerals, or mineral assemblages.

b. A variation in the composition of a crystal from core to margin, due to a separation of the crystal phases during its growth, by loss of equilibrium in a continuous reaction series. The higher-temperature phases of the isomorphic series form the core, with the lower-temperature phases toward the margin. Syn: zonal structure. c. Concentric layering parallel to the periphery of a crystal, shown by color banding, such as in tourmaline, and by differences in optical reactions to polarized light, such as in plagioclase feldspar. CF: undulatory extinction. d. In a mineral deposit, the occurrence of successive minerals or elements outward from a common center. e. The development of areas of metamorphosed rocks that may exhibit zones in which a particular mineral or suite of minerals is predominant or characteristic, reflecting the original rock composition, the pressure and temperature of formation, the duration of metamorphism, and whether or not material was added or removed.

zoning of ore deposits
 * Spatial distribution patterns of elements, minerals, or mineral assembalages; paragenetic sequences, either syngenetic or epigenetic. Zoning is esp. well developed in the mineralization-alteration assemblages about subvolcanic occurrences such as porphyry base-metal deposits. See also: zonal theory. Syn: mineral zoning.

zonite
 * A name that has been used in Arizona for locally occurring jasper or chert of various colors.

zonochlorite
 * A light and dark green variety of pumpellyite in green pebbles of banded structure; occurs in the Lake Superior region, MI.

Zonolite
 * A trade name for a light, flaky material obtained by roasting vermiculite, which swells to 15 times its original volume, forming golden yellow scales; from Libby, MT. A titanium-bearing jefferisite from Westcliffe, CO., is similar.

zooplankton
 * The animal forms of plankton, e.g., jellyfish. They consume phytoplankton.

zorgite
 * A brass-yellow metallic mineral with dark yellow streak; possibly clausthalite with umangite.

Z reagent
 * Any of the Dow series of xanthate flotation reagents.

zunyite
 * An isometric mineral, Al (sub 13) Si (sub 5) O (sub 20) (OH,F) (sub 18) Cl; occurs in transparent tetrahedral crystals, also minute cubes; at the Zuni Mine, Silverton, CO. Also spelled zungite.

zurron
 * A rawhide sack that holds about 150 lb (68.1 kg); used by miners for carrying ore.

zwieselite
 * A monoclinic mineral, (Fe,Mn) (sub 2) (PO (sub 4) )F; forms a series with triplite; clove-brown.