Dimorphous
means that two minerals have the same basic chemistry, but have different
crystal structures. And of course, Trimorphous involves three minerals and Polymorphous is when four or more minerals have the same basic
chemistry but have
different structures.
A
good example of trimorphism is Andalusite,
Kyanite
and Sillimanite.
All three have the same basic chemistry, Al2SiO5,
but Andalusite is Orthorhombic, Kyanite is Triclinic
and Sillimanite is Orthorhombic.
Dimorphous
Minerals
Anorthite
(triclinic) :: Svyatoslavite (orthorhombic)
Boracite
(orthorhombic) :: Trembathite (trigonal)
Catapleiite
(monoclinic) :: Gaidonnayite (orthorhombic)
Cavansite
(orthorhombic) :: Pentagonite (orthorhombic)
Cordierite
(orthorhombic) :: Indialite (hexagonal)
Cubanite
(orthorhombic) :: Isocubanite (isometric)
Natrolite
(orthorhombic) :: Gonnardite (orthorhombic)
Phosphosiderite
(monoclinic) :: Strengite (orthorhombic)
Pyroxmangite
(triclinic) :: Rhodonite (triclinic)
Kurnakovite
(monoclinic) :: Inderite (triclinic)
Lepidocrocite
(orthorhombic)
:: Goethite (orthorhombic)
Zircon
(tetragonal)
:: Reidite (tetragonal)
Zoisite
(orthorhombic) :: Clinozoisite (monoclinic)
Trimorphous
and Polymorphous
Minerals
Anatase
(tetragonal) :: Brookite (orthorhombic) :: Rutile
(tetragonal)
Andalusite
(orthorhombic)
:: Kyanite (triclinic) :: Sillimanite (orthorhombic)
Aragonite
(orthorhombic)
:: Calcite (trigonal) :: Vaterite (hexagonal)
Forsterite
(orthorhombic)
:: Ringwoodite (isometric) :: Wadsleyite (orthorhombic)
Diamond
(isometric)
:: Chaoite (hexagonal) :: Graphite (hexagonal) ::
Lonsdaleite (hexagonal)
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