Peach Stilbite on Basalt
Stilbite-Ca · Mineral Specimen
Crystal System
Monoclinic system, typically forming sheaf-like or bowtie aggregates, and prismatic crystals
Mineral Group
Silicates (Subgroup: Tectosilicates, Zeolite group)
Chemical Formula
NaCa4(Si27Al9)O72·28H2O
Formation Process
Hydrothermal and secondary low-temperature alteration processes filling cavities in volcanic rocks like basalt
About This Crystal
This specimen features a cluster of interlocking peach to pale orange, translucent to transparent crystal blades lining a cavity within a dark green basalt matrix. The crystals exhibit a characteristic pearly to vitreous luster with distinct cleavage faces.
Physical Characteristics
Color ranges from peach, pink, to yellowish-white; white streak; perfect cleavage on {010}; uneven fracture; specific gravity around 2.1 to 2.2; brittle tenacity; may show weak white or bluish fluorescence under UV light
Optical Properties
Biaxial (-) with refractive indices around nα = 1.484 - 1.490, nβ = 1.488 - 1.494, nγ = 1.489 - 1.496; low birefringence; low dispersion
Hardness & Durability
Origin Region
Notable sources include India (Deccan Traps), Iceland, and the USA (New Jersey); formed in basalt cavities and volcanic vesicles
Hardness & Durability
Mohs hardness of 3.5 to 4; low durability due to perfect cleavage and softness, making it unsuitable for rings or bracelets; sensitive to sudden temperature changes and acids
Care & Maintenance
Clean gently with warm, soapy water and a soft brush; avoid ultrasonic and steam cleaners, harsh chemicals, and prolonged exposure to direct sunlight or high heat due to water content
Rarity & Value
Common to uncommon mineral specimen; value depends on color intensity, crystal size, undamaged condition, and aesthetic matrix presentation
Special Characteristics
Belongs to the zeolite family, known for porous structures that allow for easy ion exchange and reversible dehydration
Lore & History
Often associated in metaphysical practices with opening the heart chakra, emotional healing, and gentle calming energies, though these are traditional beliefs and not scientific claims