Sillimanite specimens for sale
2 for sale · $2,450–$2,750 USD
14 in the gallery
Sillimanite is an aluminosilicate mineral that forms in high-temperature metamorphic rocks and contact metamorphic aureoles. It typically occurs as elongated, prismatic crystals or silky, fibrous masses with a vitreous to pearly luster and a color range from colorless to pale gray or yellowish hues. Habit can be needle-like fibers, acicular aggregates, or stout prisms, reflecting its composition and the conditions under which it grew.
- Formula
- Al2(SiO4)O
- Rarity
- Common
- Stability
- Stable
- Collector interest
- High Interest
- Classification notes
- Silicate minerals; Nesosilicates (Strunz 9.A)
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Where Sillimanite is found
About Sillimanite
Notable localities include Myanmar, Sri Lanka, India, and the United States, where well-formed crystals and fashionably textured masses have attracted collectors. Specimens from these regions often showcase clean, sharp prisms or dramatic fibrous tufts that stand out under hand lenses and display good transparency in brighter light. Sillimanite is frequently associated with kyanite and andalusite in metamorphic belts, offering context for field collectors who pursue included mineral assemblages and regional parageneses.
Collectors value sillimanite for its wide color range, structural versatility, and the striking appearance of needle-like and tabular forms. The mineral’s durability and distinctive luster make it a favorable addition to balanced cabinets, especially when paired with related aluminosilicates to illustrate metamorphic grade and mineral stability at high temperatures.