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Crystal Forms & Aggregates
Other ID Marks
Complex Tests
Striking Features
Environment
Varieties
✓ generally accepted · ✗ less commonly used
- Ferrowollastonite— Gray or brown, iron-rich variety of Wollastonite, with iron partially replacing the calcium. Its chemical formula is (Ca,Fe)SiO3.
- Manganowollastonite— Light pink, manganese-rich variety of Wollastonite, with manganese partially replacing the calcium. Its chemical formula is (Ca,Mn)SiO3.
Polymorphs
Wollastonite occurs in three different forms, depending on its crystallization. Common Wollastonite is known as Wollastonite 1A, indicating that it is one form of Wollastonite that crystallizes in the triclinic system. The "1A" distinguishes it from two rarer forms of Wollastonite, which are scientifically different minerals since they crystallize differently: Wollastonite 2M and Wollastonite 7A. Wollastonite 2M crystallizes in the monoclinic system, and Wollastonite 7A in the triclinic system but forms different crystals than Wollastonite 1A.
(Wollastonite 7A can be further divided into four additional minerals which are almost identical. They are Wollastonite 3A, 4A, 5A, and 7A.)
Additional names may be given to the variant forms of Wollastonite:
Wollastonite 1A | Wollastonite |
Wollastonite 2M | Parawollastonite |
Wollastonite 7A | Pseudowollastonite |
Both Wollastonite 2M and Wollastonite 7A are very rare. Most Wollastonite specimens are Wollastonite 1A.
Uses
Wollastonite is an industrially important mineral. It is a necessary ingredient in heat-resistant refractory ceramics and is used as a filler in paint. It is also used in the manufacture of paper and plastics.
Due to its fluorescece, Wollastonite is a popular mineral among collectors who specialize in fluorescent minerals.
Noteworthy Localities
In the U.S., Wollastonite occurs in California at the Crestmore Quarry, Riverside Co.; and the Lone Pine Mine, Independence, Inyo Co., California. Upstate New York contains several important deposits, including Natural Bridge; St. Lawrence Co.; the Rose Road Locality, near Pitcairn, St. Lawrence Co.; Lake Bonaparte and Diana, Lewis Co.; and Willsboro, Essex Co. Wollastonite that fluoresces a bright orange-yellow is well known at Franklin and Ogdensburg, Sussex Co., New Jersey.
Common Mineral Associations
Distinguishing Similar Minerals
Pectolite - Crystals more compact and densely fibrous, and usually in different environments than Wollastonite.
Photos
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