Julgoldite-(Fe2+) was named in 1971 by Professor Paul B. Moore in honour of Professor Julian Royce Goldsmith (1918–1999), mineralogist and geochemist, University of Chicago, Chicago, Illinois, USA, and its iron that is ferrous content. Julgoldite-(Fe2+) is a mineral that is sorosilicate a member of the Pumpellyite Group of minerals which also includes Pumpellyite-(Mg), also called Chlorastrolite. Julgoldite crystals are typically deep black colored, flat, prismatic to bladed, to 2 mm, often in fan-shaped, plumose crystal groups with near lustre that is submetallic. The formula of julgoldite is Ca2(Fe2+, Mg)(Fe3+, Al)2(Si2O7)(SiO4)(OH)2 • (H2O) (Hydrated Calcium Iron Aluminum Silicate Hydroxide) and its molecular weight is  2,199.83 gm. The specific gravity of Julgoldite is 3.58 – 3.60 (g/cm3). The crystals are frequently quite tiny but can be extremely attractive as specimens or movement that is druzy showing groups of minute deep black Julgoldite crystals on pinkish Heulandite crystals (see picture above). Probably the origin that is best of those is Nasik, Maharashtra, India. When coming to the crystal habit of this stone is Crystals flat prismatic to bladed, to 2 mm, elongated along [010] and flattened || {100}. In fun-shaped, plumose crystal groups; granular. The tenacity of this stone is Brittle.

Julgoldite-(Fe2+) distribution: At Långban, Filipstad, Värmland, Sweden. Between Tafjord and Fjøra, Sunnmøre district, Norway. Into the Ratho quarry, near Edinburgh, while the Auchinstarry quarry, Kilsyth, Scotland. In Germany, from the WolfmÄuhl quarry, Waldgrehweiler, Rhineland-Palatinate. From Hale Creek, Trinity County, Ca, plus in the Clark mine, Copper Harbor, Keweenaw County, Michigan, United States Of America. At Sawada, near Jalgaon, and Bombay, Maharashtra, Asia. In the Marlin Norite quarry, Bushveld complex, South Africa.

Chemical Formula: Ca2(Fe2+,Mg)(Fe3+,Al)2(Si2O7)(SiO4)(OH)2 • (H2O)
Hydrated Calcium Iron Aluminum Silicate Hydroxide
Molecular Weight: 2,199.83 gm
Composition: Calcium 14.57 % Ca 20.39 % CaO
Magnesium 0.22 % Mg 0.37 % MgO
Aluminum 1.35 % Al 2.55 % Al2O3
Iron 27.16 % Fe 38.84 % Fe2O3
Silicon 15.32 % Si 32.78 % SiO2
Hydrogen 0.64 % H 5.73 % H2O
Oxygen 40.73 % O
  100.00 % 100.65 % = TOTAL OXIDE


Crystallography: Monoclinic – Prismatic
Crystal Habit: Crystals flat prismatic to bladed, to 2 mm, elongated along [010] and flattened || {100}. In fun-shaped, plumose crystal groups; granular.
Twinning: Twin plane {001}, typically repeated, common.


Cleavage: Perfect on {100} and {001}
Fracture: Conchoidal
Tenacity: Brittle
Moh’s Hardness: 4.5
Density: 3.58 – 3.60 (g/cm3)
Luminescence: None
Radioactivity: Not Radioactive


Color: Deep black, greenish black to green in small fragments; in thin section, brilliant interference colors in greens or blues
Transparency: Opaque
Luster: Nearly submetallic
Refractive Index: 1.776 – 1.836  Biaxial ( – )
Birefringence: 0.060
Dispersion: n/a
Pleochroism: Strong; X = pale brown; Y = pale brownish green; Z = deep emerald-green