THE MINERAL MENEGHINITE

• Chemistry: Pb₁₃Sb₇S₂₃, Lead Antimony Sulfide
• Class: Sulfides
• Subclass: Sulfosalts
• Uses: Mineral specimens and as a very minor ore of lead.
• Specimens

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Meneghinite is a rare mineral that generally forms interesting acicular crystals. Meneghinite is one of several lead antimony sulfides. The elements lead, antimony and sulfur have the capability of forming many different minerals. There are at least a dozen different minerals with just lead, antimony and sulfur comprising their chemistries. All of those minerals are sulfosalts, a segment of sulfides where the antimony acts more like a metal than a non-metal and occupies a position where it is bonded to sulfurs. They have some very similar properties such as a gray color, high density, low hardness, metallic luster, dark gray to black streaks and a similar environment of formation. Most form from hydrothermal fluids that crystallize at lower temperatures than other sulfides. They can be distinguish only by differences in their respective crystal habits, cleavages, fracture and x-ray techniques. The table below shows most of the lead antimony sulfides and their formulas (some have additional elements).

MINERAL	FORMULA	MINERAL	FORMULA	MINERAL	FORMULA
ANDORITE	PbAgSb3S6	BOULANGERITE	Pb5Sb4S11	FREIESLEBENITE	PbAgSbS3
FULOPPITE	Pb3Sb8S15	GEOCRONITE	Pb14(Sb, As)6S23	GUETTARDITE	Pb(Sb, As)2S4
HETEROMORPHITE	Pb7Sb8S19	JAMSONITE	Pb13FeSb7S23	LAUNAYITE	Pb22Sb26S61
MENEGHINITE	Pb13Sb7S23	PARAJAMSONITE	Pb4FeSb7S23	PLAGIONITE	Pb5Sb8S17
PLAYFAIRITE	Pb16Sb18S43	ROBINSONITE	Pb4Sb6S13	SEMSEYITE	Pb9Sb8S21
SORBYITE	Pb19(Sb, As)20S49	TWINNITE	Pb(Sb, As)2S4	ZINKENITE	Pb9Sb22S42

PHYSICAL CHARACTERISTICS OF MENEGHINITE:

• Color is lead gray to black.
• Luster is metallic.
• Transparency: Crystals are opaque.
• Crystal System: Orthorhombic: 2/m 2/m 2/m.
• Crystal Habits include common acicular to prismatic, granular and even some fibrous crystals and massive forms.
• Cleavage is perfect in one direction (prismatic).
• Hardness is 2.5
• Specific Gravity is 6.3 - 6.4 (heavier than average for metallic minerals)
• Streak is steel gray.
• Associated Minerals include calcite, galena, sphalerite, tetrahedrite, arsenopyrite and several other sulfosalts.
• Notable Occurrences include the type locality of Bottino Mine, Serravezza, Alpe Apuane, Toscana, Italy as well as Chamonix Valley, France; Turkey; Kalkar Quarry, Santa Cruz County, California, USA and Marble Lake, Frontenac County, Ontario, Canada.
• Best Field Indicators are crystal habit, associations, cleavage, locality and density.