Lansfordite is a mineral of

magnesium carbonate Magnesium carbonate, (archaic name magnesia alba), is an inorganic salt that is a colourless or white solid. Several hydrated and Base (chemistry), basic forms of magnesium carbonate also exist as minerals. Forms The most common magnesium car ...

(). It represents the pentahydrate of magnesium carbonate, and has the total formula . Landsfordite was discovered in 1888 in a

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

mine in

Lansford, Pennsylvania Lansford is a border, county-border borough (Pennsylvania), borough (town) in Carbon County, Pennsylvania, United States. It is part of Northeastern Pennsylvania. It is located northwest of Allentown, Pennsylvania, Allentown and 19 miles south ...

. It crystallizes in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...

system (space group ''P2₁/c'') and typically occurs as colorless to white prismatic crystals and stalactitic masses. It is a soft mineral,

Mohs hardness The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fair ...

of 2.5, with a low

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

of 1.7. It is transparent to translucent with

refractive indices In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...

of 1.46 to 1.51. The mineral will effloresce at room temperature, producing

nesquehonite Nesquehonite is a mineral of magnesium carbonate (). It represents the trihydrate of magnesium carbonate, and has the total formula . It was described in 1890 by F. A. Genth and S. L. Penfield and is named after its type locality of Nesquehoni ...

References

Magnesium minerals Carbonate minerals Geology of Pennsylvania Monoclinic minerals Pentahydrate minerals Minerals in space group 14 Minerals described in 1888 {{carbonate-mineral-stub