Formula :
Ca2Cu9(AsO4)4(SO4)0.5(OH)9 · 9H2O
System: monoclinic Hardness:2 - 2˝ Rarity:rare
Strunz id:VIII/B.9-05 -
SILICATES
Name origin: Named after the type locality.-Tangdan Mine, Dongchuan Cu ore field, Dongchuan District, Kunming Prefecture, Yunnan Province, China
"Clinotyrolite" was published without CNMMN approval because the authors thought it is different from tyrolite (which was considered to be orthorhombic at that time). However, tyrolite was later shown to be monoclinic(-pseudo-orthorhombic), with at least two monoclinic polytypes being detected (Krivovichev et al., 2006); one of them seems to be identical to "clinotyrolite".
Since it is well-known that also carbonate-free varieties of tyrolite exist, "tyrolite" may actually represent more than two minerals/polytypes.
In 2014, clinotyrolite was discredited due to being identical with the (approved) tangdanite.
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