Hodgkinsonite

Hodgkinsonite is a mineral that is a very unusual gem. Hodgkinsonite is amongst the rarest of all collector gems. It had been found in 1913 at the Franklin Mining District, Sussex County, brand new Jersey, USA. This is actually the location that is only finding Hodgkinsonite in the world. It is one of many minerals available at this location and nowhere else. Hodgkinsonite has mined down years ago and the mines have now been closed. Hodgkinsonite could be the product of the metamorphism of other zinc minerals such as Hemimorphite and Smithsonite. It’s an extremely mineral that is attractive is available in bright pink to lavender colors. Gems can be quite attractive with colors of bright pink, red to reddish brown, orange, or hardly ever yellow but are usually extremely tiny due to a crystal that is small.

Category:	Nesosilicate
Chemical Formula:	Mn2+Zn2(SiO4)(OH)2
	Zinc Manganese Silicate Hydroxide
Molecular Weight:	311.82 gm

Composition:	Manganese	17.62 %	Mn	22.75 %	MnO
	Zinc	41.94 %	Zn	52.20 %	ZnO
	Silicon	9.01 %	Si	19.27 %	SiO2
	Hydrogen	0.65 %	H	5.78 %	H2O
	Oxygen	30.79 %	O
		100.00 %		100.00 %	= TOTAL OXIDE

 

Crystallography:	Monoclinic – Prismatic
Crystal Habit:	As euhedral crystals, stout prismatic and terminated by steep pyramids, also dominated by pyramidal forms, to 2 cm. Granular to massive in veinlets.
Twinning:	None

 

Cleavage:	Perfect on {001}
Fracture:	Conchoidal
Tenacity:	Brittle
Moh’s Hardness:	4.5 – 5.0
Density:	4.06 – 4.08 (g/cm3)
Luminescence:	Not often fluorescent, but some specimens have shown a red, weak pink or dull dark purple fluorescence under longwave UV light.
Radioactivity:	Not Radioactive

 

Color:	Bright Pink or Red to Reddish Brown and Orange, rarely Yellow; Black from tarnish or inclusions.
Transparency:	Transparent, Translucent to Opaque
Luster:	Vitreous
Refractive Index:	1.720 – 1.746  Biaxial ( – )
Birefringence:	0.0260
Dispersion:	Strong to moderate; r > v or r < v
Pleochroism:	Distinct; in shades of lavender and pale purple.