The Collaborative International Dictionary of English v.0.48:

Gold \Gold\ (g[=o]ld), n. [AS. gold; akin to D. goud, OS. & G.
   gold, Icel. gull, Sw. & Dan. guld, Goth. gul[thorn], Russ. &
   OSlav. zlato; prob. akin to E. yellow. [root]49, 234. See
   Yellow, and cf. Gild, v. t.]
   [1913 Webster]
   1. (Chem.) A metallic element of atomic number 79,
      constituting the most precious metal used as a common
      commercial medium of exchange. It has a characteristic
      yellow color, is one of the heaviest substances known
      (specific gravity 19.32), is soft, and very malleable and
      ductile. It is quite unalterable by heat (melting point
      1064.4[deg] C), moisture, and most corrosive agents, and
      therefore well suited for its use in coin and jewelry.
      Symbol Au (Aurum). Atomic weight 196.97.
      [1913 Webster]

   Note: Native gold contains usually eight to ten per cent of
         silver, but often much more. As the amount of silver
         increases, the color becomes whiter and the specific
         gravity lower. Gold is very widely disseminated, as in
         the sands of many rivers, but in very small quantity.
         It usually occurs in quartz veins (gold quartz), in
         slate and metamorphic rocks, or in sand and alluvial
         soil, resulting from the disintegration of such rocks.
         It also occurs associated with other metallic
         substances, as in auriferous pyrites, and is combined
         with tellurium in the minerals petzite, calaverite,
         sylvanite, etc. Pure gold is too soft for ordinary use,
         and is hardened by alloying with silver and copper, the
         latter giving a characteristic reddish tinge. [See
         Carat.] Gold also finds use in gold foil, in the
         pigment purple of Cassius, and in the chloride, which
         is used as a toning agent in photography.
         [1913 Webster]

   2. Money; riches; wealth.
      [1913 Webster]

            For me, the gold of France did not seduce. --Shak.
      [1913 Webster]

   3. A yellow color, like that of the metal; as, a flower
      tipped with gold.
      [1913 Webster]

   4. Figuratively, something precious or pure; as, hearts of
      gold. --Shak.
      [1913 Webster]

   Age of gold. See Golden age, under Golden.

   Dutch gold, Fool's gold, Gold dust, etc. See under
      Dutch, Dust, etc.

   Gold amalgam, a mineral, found in Columbia and California,
      composed of gold and mercury.

   Gold beater, one whose occupation is to beat gold into gold
      leaf.

   Gold beater's skin, the prepared outside membrane of the
      large intestine of the ox, used for separating the leaves
      of metal during the process of gold-beating.

   Gold beetle (Zool.), any small gold-colored beetle of the
      family Chrysomelid[ae]; -- called also golden beetle.


   Gold blocking, printing with gold leaf, as upon a book
      cover, by means of an engraved block. --Knight.

   Gold cloth. See Cloth of gold, under Cloth.

   Gold Coast, a part of the coast of Guinea, in West Africa.


   Gold cradle. (Mining) See Cradle, n., 7.

   Gold diggings, the places, or region, where gold is found
      by digging in sand and gravel from which it is separated
      by washing.

   Gold end, a fragment of broken gold or jewelry.

   Gold-end man.
      (a) A buyer of old gold or jewelry.
      (b) A goldsmith's apprentice.
      (c) An itinerant jeweler. "I know him not: he looks like a
          gold-end man." --B. Jonson.

   Gold fever, a popular mania for gold hunting.

   Gold field, a region in which are deposits of gold.

   Gold finder.
      (a) One who finds gold.
      (b) One who empties privies. [Obs. & Low] --Swift.

   Gold flower, a composite plant with dry and persistent
      yellow radiating involucral scales, the Helichrysum
      St[oe]chas of Southern Europe. There are many South
      African species of the same genus.

   Gold foil, thin sheets of gold, as used by dentists and
      others. See Gold leaf.

   Gold knobs or Gold knoppes (Bot.), buttercups.

   Gold lace, a kind of lace, made of gold thread.

   Gold latten, a thin plate of gold or gilded metal.

   Gold leaf, gold beaten into a film of extreme thinness, and
      used for gilding, etc. It is much thinner than gold foil.


   Gold lode (Mining), a gold vein.

   Gold mine, a place where gold is obtained by mining
      operations, as distinguished from diggings, where it is
      extracted by washing. Cf. Gold diggings (above).

   Gold nugget, a lump of gold as found in gold mining or
      digging; -- called also a pepito.

   Gold paint. See Gold shell.

   Gold pheasant, or Golden pheasant. (Zool.) See under
      Pheasant.

   Gold plate, a general name for vessels, dishes, cups,
      spoons, etc., made of gold.

   Mosaic gold. See under Mosaic.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mine \Mine\, n. [F., fr. LL. mina. See Mine, v. i.]
   [1913 Webster]
   1. A subterranean cavity or passage; especially:
      (a) A pit or excavation in the earth, from which metallic
          ores, precious stones, coal, or other mineral
          substances are taken by digging; -- distinguished from
          the pits from which stones for architectural purposes
          are taken, and which are called quarries.
      (b) (Mil.) A cavity or tunnel made under a fortification
          or other work, for the purpose of blowing up the
          superstructure with some explosive agent.
          [1913 Webster]

   2. Any place where ore, metals, or precious stones are got by
      digging or washing the soil; as, a placer mine.
      [1913 Webster]

   3. (Fig.): A rich source of wealth or other good. --Shak.
      [1913 Webster]

   4. (Mil.) An explosive device placed concealed in a location,
      on land or at sea, where an enemy vehicle or enemy
      personnel may pass through, having a triggering mechanism
      which detects people or vehicles, and which will explode
      and kill or maim personnel or destroy or damage vehicles.
      A mine placed at sea (formerly called a torpedo, see
      torpedo[2]
      (a) ) is also called an marine mine and underwater mine
          and sometimes called a floating mine, even though it
          may be anchored to the floor of the sea and not
          actually float freely. A mine placed on land (formerly
          called a torpedo, see torpedo[3]), usually buried,
          is called a land mine.
          [PJC]

   Mine dial, a form of magnetic compass used by miners.

   Mine pig, pig iron made wholly from ore; in distinction
      from cinder pig, which is made from ore mixed with forge
      or mill cinder.

   gold mine
      (a) a mine where gold is obtained.
      (b) (Fig.) a rich source of wealth or other good; same as
          Mine 3. --Raymond.
          [1913 Webster]

WordNet (r) 3.0 (2006):

gold mine
    n 1: a good source of something that is desired [syn:
         goldmine, gold mine]
    2: a mine where gold ore is found [syn: goldmine, gold mine]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "gold mine":
   Eldorado, Golconda, bank, bonanza, coal mine, colliery, cornucopia,
   diggings, eldorado, font, fount, fountain, gravy train, lode, mine,
   mine of wealth, mother lode, open cut, opencast, pit, quarry,
   resource, rich lode, rich uncle, shaft, source, source of supply,
   spring, staple, treasure trove, treasure-house, treasury, vein,
   well, wellspring, workings