F A C E T - N A T I O N

         

HEMATITE (also spelled haematite), Fe2O3

   
   
D. Hematite. Crystal group (greatest dimension - 3.5 cm) from N'Chwaning II mine, Kalahari Manganese Field, South Africa:  oil painting (40 x 54 cm) by Rainer Jäckle, owner of the specimen. (© photo by R. Jäckle)

DESCRIPTION: Lustrous botryoidal or stalactitic masses, frequently called "kidney iron ore," and individual crystals of the hematite variety, commonly called specular hematite or specularite, are used as the rough material for fashioning gemstones and ornamental pieces. The former material is a gemrock (see Figure C), the latter is in essence a gem mineral (see Figure D).  The following properties obtain for both materials:
    Color - steel gray to nearly black
    H. 5-6½
    S.G. ~ 5.25
    Light transmission - opaque
    Luster - dull to highly lustrous -- i.e., submetallic;  polished surfaces are brilliant.
    Miscellany -  streak (color of powder) -- red;  soluble in acid.

A second "new type of haematite" also used as a gemrock has been described by Schmetzer and Bank (1984) as a granular material consisting largely of hematite plus minor amounts of magnetite, martite and gangue minerals. This granular material is described as typically bluish gray, having a dark brown streak, and magnetic,  and that polished surfaces of it tend to be slightly pitted.

OTHER NAMES:  In addition to the below-listed terms, which are applied to hematite or hematite-rich gemrocks, several other gemrocks and a few gem minerals owe their red color and or other desirable characteristics to the presence of hematite, and thus warrant mentioning here.  Examples include the following:  hemachate (haemachates) -- see CHALCEDONY entry;  red jasper -- see JASPER entry;  rubasse (rubace, rubacelle) - see Appendix A;  sunstone - a hematite-bearing  feldspar (oligoclase) gemstone;  tiger iron -- see HAWK'S-EYE...entry.

  • Alaskan diamond or Alaskan black diamond - trade name sometimes given beads, cabochons etc. fashioned from mammillary masses of fibrous specular hematite, some of which has been called pencil ore.
  • Black diamond - variant of names in preceding listing.
  • Blood stone - this name, applied more widely to a variety of chalcedony (q.v.), has been applied to some hematite because of the red powder it yields when crushed.
  • Drusy hematite - hematite masses from the Bradshaw Mountains of Arizona, that have been cut and polished to form tablets (etc.), which are described as having "a velvety surface -- similar to 'rainbow hematite' without the play of color ... " (Johnson et al., 2000).
  • Glaskopf (sometimes called orbicular hematite) - name applied to gemrock hematite said to consist of radial fibers; some of this material may be goethite ("limonite") rather than hematite.
  • Granular hematite - an intergrowth consisting largely of granular hematite plus lesser percentages of magnetite and martite from Quadrilatero Ferrifero, near Ouro Preto,  Mina Gerais, Brazil.
  • Iridescent specularite - a shale or slate, reputed to be hematite-rich, that exhibits multicolored surfaces that resemble oil slicks on water;  according to Kammerling, Koivula, and Fritsch, (1995, p.137), Robert Poley, a "miner" from Prescott, Arizona who was marketing the material, stated that it had taken on its appearance as the result of either exposure on mine dumps or being left, along  with an iron nail, in a bucket of water.
  • Oolitic hematite - the Silurian Clinton Formation "iron ore" of the Appalachians is an example, albeit only in some nomenclature schemes: Although I have mapped and studied this formation, I have neither seen specimens nor know of any well-documented examples of this rock's being used in necklaces, earrings or as "tumbled pieces" and used in necklaces and for earrings.   However, some hematite pigmented oolitic jasper, such as that constituting pebbles I have picked up on Lake Michigan and Lake Superior certainly could be fashioned into striking beads, earrings, small pendants, etc. -- See JASPER entry. 
     
  • Specularite (specular hematite) - the varietal name for most of the hematite used as gemrock.  (This name is not to be confused with spectrolite, the name sometimes applied to the labradorite/anorthosite gemrock from Finland -- See ANORTHOSITE entry.)
  • Rainbow hematite - trade name given masses of foliated specular hematite from a mine near Belo Horizonte, Minas Gerais, Brazil.  At least some of the material so-marketed appears to owe its iridescence to a coating of titanium (hearsay) or aluminum and phosphorus (Koivula, Kammerling and Fritsch, 1993);  more recent investigations, however, appear not to support the identity of the coating as aluminum and phosphorus (George Rossman, personal communication, 2002).

USES: Hematite was used for making seals in Babylonia as early as 1900-1300 B.C. Hematite once found use in mourning jewelry and hematite intaglios were relatively popular as stickpins (i.e., for ties), especially in the early part of the 20th century.  More recently, hematite has gained popularity as cabochons and as spherical, faceted, and tumbled irregularly shaped beads.  Despite its attractive appearance, such necklaces and earrings have found only relatively limited because of hematite's relatively high specific gravity -- many who have such jewelry complain that it is too heavy to wear over any extended period of time. Nonetheless, hematite jewelry continues to be fashioned and widely marketed. My observations suggest that necklaces made of relatively small spherical beads, which resemble black pearls, and relatively small faceted or tumbled pieces are worn most frequently and I suspect will likely have a good continuing market.  Other uses include diverse ornaments, paper weights, and polished spheres and eggs.  Also, rather recently, relatively flat pieces of botryoidal hematite have been fashioned to exhibit their natural shapes, which are described as resembling cumulus clouds (Johnson et al., 2000).  And, because of its unique appearance it seems likely that rainbow hematite may receive a fair amount of attention in the future.

OCCURRENCES: Hematite used as a gemrock occurs as microcrystalline masses comprising nodules, etc.;  the granular "new ... haematite" occurs like many hematite ores.

NOTEWORTHY LOCALITIES: Cumbria (in part formerly Cumberland), England; here and there in Germany, Norway, Sweden, Morocco, Canada and New Zealand; the island of Elba; Black Widow mine, Pima County, Arizona; Lake Superior district of Minnesota, Wisconsin and Michigan. The granular "new ... haematite" has been recorded as occurring in the Quadrila'tero Ferrifero area near Ouro Preto, Minas Gerais, Brazil.

REMARKS:  Theophrastus' “On Stones” (~315 B.C.)  is the earliest known reference to what is thought now to have been hematite;   his name for the material, which translates to bloodstone, was apparently based on the fact that its red powder indicated it possibly represented coagulated blood.  Some four hundred years later, Pliny, the Elder  (pre-79 A.D, Book  xxxvii) used hæmatites, the Latin equivalent,  in his widely cited Historia  Naturalis.   The varietal name specularite (and the adjective specular) come from the Latin word for mirror, apparently reflecting (no pun intended) that use of highly lustrous black hematite.

The  redness of hematite powder was an early recognized characteristic and, in ancient times, this property led to its being fashioned into amulets used to ward off or stop bleeding.  Later, according to Pliny, the Elder (op cit.), hematite was described in volumes about precious stones written by Zachalias of Babylon and dedicated to Mithridates the Great, King of Pontus (d.63 B.C.)  as having all sorts of attributes -- e.g., curing diseases of the eyes and liver, aiding those in battle, and even helping petitioners in trials.

Some people consider small hematite spheres to constitute an excellent substitution for black pearls. As already mentioned, however, apparently at least some of those who wear them find strings of hematite beads too heavy to wear comfortably except for short periods of time.

The following is recorded on the web site www.beringseaoriginals.com:  “Hematite has long since been part of our heritage here in Alaska and  Russia since the early days before Alaska was purchased by the United States.  Lord Baranof once had skilled Aleut Silversmiths make hematite into rings and pendants. [and] This beautiful Black Diamond [-- as already noted, the name often applied to hematite, particularly in Alaska --] was presented to the Royal Family of Czar Alexander I as a Royal gift from his Alaskan Subjects to show their faithfulness to the Great Czar.”

Hematite (though not as a gemrock) is the state mineral of Alabama.

SIMULANTS:

***Barium iron oxide (synthetic BaF12O19) - material constituting bracelets said to have been made in China and sold "all over Europe as hematite" was determined to have this composition (E. Fritsch in Johnson et al., 2000). - [This material is highly magnetic whereas typical hematite is not and even some atypically magnetic hematite is only slightly magnetic.].

Black pearl - potential, but why? -- the opposite (i.e., hematite as a simulant for black pearls) makes a lot more sense. - [inferior specific gravity].

Cut steel - steel, usually "cut" to give it several facets, was used – especially during the late 1700s – for such diverse things as shoe buckles, hair ornaments and jewelry.   Subsequently, especially during  the 1800s,  steel with a similar appearance was fashioned by stamping, rather than cutting, and used for the same general purposes. - [For pieces that resemble hematite, the fact that the steel that was used is strongly magnetic suffices to distinguish it from hematite.]

***Glass - [conchoidal fracture;  specific gravity less than half that of hematite].

***Hemalyke - name given to what amounts to restructured/reconstructed hematite -- i.e., it consists of ground up hematite plus some binder that is pressed and then molded or faceted into items commonly fashioned from natural hematite. - [Distinquishing this material from natural hematite often requires non-macroscopic observations.].

***Hematite garnet - material reportedly synthesized in Zimbabwe - [lower specific gravity (S.G. ~4.16)].

***Hemetine - trade name given a hematite simulant used widely for intaglios, at least some of which have been produced by stamping rather than carving.  According to the "Dictionary of gems and gemology ... " (GIA, 1974), "The raw material [originally] used ... was galena ..., resulting in a black streak and a heavy specific gravity.... [But.]  more recent material contains mainly iron and titanium oxides, resulting in a red-brown streak and nearly the same specific gravity ... and hardness ... as hematite."  Stainless steel has also been recorded as a major constituent of some hemetine. - [In addition to the just mentioned differences, at least some hemetine is strongly magnetic.].

Magnetite (including lodestone) - rarely fashioned into gemstones that resemble hematite - [Magnetite is strongly magnetic whereas hematite is at most weakly magnetic.].

Psilomelane - sometimes marketed as hematite - [Luster appears more satinlike and streak (color of powder) is brown whereas that of hematite is red.].

"Scientific hematite" - name given to "a white metal ... found to be a typical stainless steel composed principally of iron and chromium with small amount of nickel ... [with its] intaglio design ... stamped into the metal ...  [and marketed as stones in ] a series of  'inexpensive rings' " (Anonymous report of American Gemological Society Research Service in "Gems & Gemology" III:112). - [Appearance suffices -- does not really look like hematite.].

Synthetic hematite - a flux grown hematite is recorded by Liddicoat (1967). - [ I suspect non-macroscopic means would be required.]. 

REFERENCES: No good general reference, but see Jones (1989)

 
 
 

 

 

 

 
 

 

 

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