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Humite
Current inventory:  0 gems
 

  
Humite is named after Sir Abraham Hume (1749-1838), English connoisseur and collector of works of art, gems, and minerals.

Discovered in 1813;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

(Mg, Fe²⁺)₇(SiO₄)₃(F, OH)₂

Magnesium Iron Silicate Fluoride Hydroxide

Molecular Weight:

538.58 gm

Composition:

Magnesium

23.69 %

Mg

39.29 %

MgO

Iron

18.15 %

Fe

23.34 %

FeO

Silicon

15.64 %

Si

33.47 %

SiO₂

Hydrogen

0.09 %

H

0.84 %

H₂O

Oxygen

37.13 %

O

Fluorine

5.29 %

F

5.29 %

F

-

-   %

F

-2.23 %

-O=F₂

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/B.04-30

Nickel-Strunz 10th Ed. ID:

9.AF.50

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination

Related to:

Humite Group

Varieties:

None

Synonyms:

Umite

Crystal Data

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

Crystals typically highly modifeed, to 1 cm; granular

Twinning:

None

Physical Properties

Cleavage:

{100} Poor

Fracture:

Uneven to Subconchoidal

Tenacity:

Brittle

Moh's Hardness:

6.0

Density:

3.20 - 3.32 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

White, Yellow, dark Orange, Brown; Colorless to Yellow-Brown in thin section

Transparency:

Transparent to Translucent

Luster:

Vitreous

Refractive Index:

1.607 - 1.675  Biaxial (+)

Birefringence:

0.032

Dispersion:

Weak; r > v

Pleochroism:

X = very pale yellow to dark yellow; Y = Z = colorless, pale yellow

Occurances

Geological Setting:

Typically in contact metamorphic zones in limestones and dolostones associated with felsic, or more rarely, alkalic plutonic rocks, especially where metasomatism has introduced Fe, B, and F.

Common Associations:

Brucite, Calcite, Corundum, Cuspidine, Diopside, Dolomite, Fluoborite, Forsterite, Grossular, Ludwigite, Monticellite, Phlogopite, Pyrrhotite, Serpentine, Spinel, Wollastonite

Common Impurities:

Al, Ca, Mn, Ti

Type Locality:

Monte Somma, Somma-Vesuvius Complex, Naples Province, Campania, Italy

Year Discovered:

1813

View mineral photos:

Humite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Humite is the principal member of the Humite Group of minerals that includes Chondrodite, Clinohumite, Humite and Norbergite. Humite is a fairly rare mineral that is found in contact metamorphic dolomitic limestones as small prismatic crystals. Humite crystals are rarely clean enough for faceting. One recent source of small gem quality crystals is the Minh Tien Mine, Luc Yen, Yenbai (Yen Bai) Province, Vietnam.

Other sources of Humite are Monte Somma and Vesuvius, Campania, Italy; Lohja, Sillböle, and Hermala, Finland; the Norberg area, and at the Ladu mine, Persberg, Värmland, Sweden; at Anzahamazonono, Madagascar; Sorfinnset, Glomfjord, Norway; Llanos de Juanar, Málaga Province, Spain; the Tilly Foster mine, Brewster, Putnam County, New York, and at Franklin, Sussex County, New Jersey, USA.
 

  
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