Name/Title
AstrophylliteEntry/Object ID
2009.62.44Description
Chemical Composition: (K,Na)3(Fe,Mn)7Ti2(SiO3)8
Crystal System: Triclinic System
Description: Common Name: Astrophyllite
Chemistry: (K,Na)3(Fe,Mn)7Ti2(SiO3)8(O,OH)7, Potassium Sodium Iron Manganese Titanium Silicate Hydroxide.
Group: Silicates
Location: Khibiny Massif, Murmansk Oblast, Russia
Description: The crystal structure has a splintery appearance on a black and white matrix
PHYSICAL CHARACTERISTICS:
Color is usually golden yellow or yellowish brown, but also greenish brown specimens are found. Luster is vitreous or submetallic to metallic, can be pearly on cleavage surfaces.
Transparency: crystals are translucent to opaque.
Crystal System is triclinic; bar 1
Crystal Habits include small tabular or bladed crystals often grouped in starlike aggregates. Also found in lamellar massives.
Cleavage is perfect in one direction.
Fracture is uneven.
Hardness is 3.
Specific Gravity is 3.3 - 3.4
Streak is yellowish white.
Associated Minerals are quartz, feldspars, nepheline, micas and aegirine.
Other Characteristics: color is often patchy or heterogenous in distribution.
Best Field Indicators brittleness, cleavage, color, luster and localities.
Fracture: uneven
Hardness: 3 Calcite
Luster: Vitreous
Occurrence: Found in cavities and fissures in unusual felsic igneous rocks, astrophyllite is associated with feldspar, mica, titanite, zircon, nepheline, and aegirine. Common impurities include magnesium, aluminium, calcium, zirconium, niobium, and tantalum.
Rock Type: Metamorphic
Specific Gravity: 3.3 - 3.4
Streak: golden
Texture: crystaline
Variety: Astrophyllite is a rare titanium mineral found in some unusual granites and syenites. It produces a variable luster that can be nearly metallic in one specimen to vitreous in another. Its name translated means star sheets and probably is in allusion to the intergrown starlike aggregates that it can formCollection
RAGM Mineral CollectionDimensions
Width
2-3/4 inDepth
1-1/2 inLength
3-1/2 inWeight
2 ozDimension Notes
Dimension taken at widest pointsLocation
Location
Display Case
FS-9Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
ExhibitMoved By
Ian C.Date
January 29, 2025Notes
Location/ inventoryLocation
Display Case
FS-4Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentDate
August 17, 2023