The Mineral SERANDITE

Chemistry: Na(Mn, Ca)2Si3O8(OH), Sodium Manganese Calcium Silicate Hydroxide
Class: Silicates
Subclass: Inosilicates
Uses: Only as mineral specimens.
Specimens

Serandite has a beautiful pink color that is only similar to only a few other minerals. Serandite is probably the most famous of the unique minerals found at the Mont. St. Hilaire, Quebec, Canada. It forms nice crystals that are often associated with other rare and interesting minerals. One of the best assortments includes the pink, elongated serandite with attached rounded, snow white analcime crystals. Classic specimens of this mineral assemblage are truly treasured by their owners.

Serandite forms a series with the mineral pectolite, NaCa2Si3O8(OH). The structures are similar but serandite has a significant percentage of manganese ions which substitute for a portion of the calciums in the pectolite. It is the manganese ions which cause the pink color of serandite. Several other manganese minerals have a distinct pink color such as the carbonate rhodochrosite and the silicates rhodonite and inesite. However serandite's color is more of a salmon pink the these pink minerals and it has a silky luster that is distinct.

PHYSICAL CHARACTERISTICS:

Color is pink to reddish pink and off white.
Luster is vitreous to silky.
Transparency crystals are transparent to translucent.
Crystal System is triclinic; bar 1
Crystal Habits include prismatic crystals with a distorted hexagonal cross-section. Also massive and compact.
Cleavage is perfect in two directions at close to right angles.
Fracture is splintery due to the cleavage.
Hardness is 4.5
Specific Gravity is approximately 3.2 - 3.4 (above average for translucent)
Streak is white.
Associated Minerals include calcite, analcime, vesuvianite, grossular garnetand many extremely rare minerals.
Notable Occurrences include the famous mines at St. Hilaire, Quebec, Canada and Roma Island, Los Islands, Guinea.
Best Field Indicators are crystal habit, color, luster, associations, locality and cleavage.