STANNITE
STANNITE Stannnite – Cu2FeSnS4 – is a relatively common sulfide. It is part of polymetallic ores, being primarily an ore of Sn (27.61% by weight), but also of Cu (29.56% by weight). It is sometimes called “bell metal ore” because it was used to obtain Sn for bell casting. It is classified in the Stannnite […]
SAFFLORITE
SAFFLORITE Safflorite – CoAs2 – is a rare arsenide that is part of Co ores. It is classified in the Löllingite Group, which consists of quite rare minerals. Pure safflorite practically never occurs; there is always an appreciable content of Fe and/or Ni replacing the Co, which is necessary for the stabilization of the structure. […]
STILBITE
STILBITE Stilbite is a relatively common tectosilicate, a mineral of the Zeolite Group that typically occurs as a secondary mineral. It has no economic importance other than collecting mineral. “Stilbite” is not actually a mineral, but just a generic term that refers to two minerals: stilbite-Ca ( NaCa4(Si27Al9)O72.28H2O ) and stilbite-Na ( Na9(Si27Al9)O72.28H2O ). The […]
SCOLECITE
SCOLECITE Scolecite – CaAl2Si3O10·3H2O – is a relatively common tectosilicate, a zeolite that typically occurs as a secondary mineral associated with basic igneous rocks. It has no economic importance other than a collecting mineral. It is classified in the Zeolite Group, in the Natrolite Subgroup, where there are three very common and similar zeolites: scolecite […]
STIBNITE
STIBNITE Stibnite – Sb2S3 – also known as antimonite, is a relatively rare sulfide, yet it is the most common sulfide of antimony (Sb) and serves as the primary ore mineral for the element. Stibnite is typically very pure. Its long prismatic crystals form radiating or randomly arranged clusters. Stibnite is dimorphous with metastibnite and […]
SAPPHIRINE
SAPPHIRINE Sapphirine – Mg4(Mg3Al8)O4(Si3Al9O20) – is a very rare inosilicate that occurs only in a few very specific geological situations. It has economic importance only as a gemstone and collector’s mineral. Macroscopically, it is very similar to serendibite (Ca2(Mg;Al)6(Si;Al;B)6O20), an extremely rare inosilicate. Sapphrine belongs to the Sapphirine Group, has two polytypes and two varieties […]
SMITHSONITE
SMITHSONITE Smithsonite – ZnCO3 – is a relatively common carbonate that often occurs as part of a mixture of Zn ore minerals called “calamine” in the mining industry. It could be a Cd ore. “Calamine” is not a mineral, but a term for a mixture of smithsonite and hemimorphite, which are identical in hand sample; […]
SPINEL
SPINEL Spinel – MgAl2O4 – is a common oxide that occurs mainly as an accessory mineral of igneous rocks. It has economic importance only as a gemstone, imitating ruby (red corundum) and sapphire (blue corundum). Synthetic spinel in sheets resembles glass, but has much greater strength. The spinel belongs to the Spinel Group and forms […]
SIDERITE
SIDERITE Siderite – FeCO3 – is a rarer carbonate of the Calcite Group, typical of hydrothermal veins with metals and an important historical iron ore, with 48% iron, no S or P, but some Mg, Mn, Ca, Zn and Co. It supplies a superior quality steel, already recognized by the Romans as “ferrum nordicum”. Its […]
SPHALERITE
SPHALERITE Sphalerite (old names: “blende”, “zinc blende”) – ZnS – is a common sulfide and the main ore of Zn. May constitute a Cd ore. Sphalerite is usually massive. Crystals are rare, tetrahedral and dodecahedral, typically very complex and distorted (conical and curved faces); can look like octahedrons, reach 30 cm. Crystals show strong brilliance […]