Amethyst and Lava Stone
Quartz var. Amethyst and Basaltic scoria · Semi-Precious Gemstone (Amethyst) and Decorative Stone (Lava Stone)
Crystal System
Trigonal (Amethyst) - commonly hexagonal prisms; Amorphous to Microcrystalline (Lava Stone) - highly vesicular habit
Mineral Group
Silicates (Tectosilicates for Amethyst; Mixed Silicates for Lava Stone)
Chemical Formula
SiO2 (Amethyst); Complex silicate mixture primarily plagioclase, pyroxene, and olivine (Lava Stone)
Formation Process
Hydrothermal/Magmatic in geodes (Amethyst); Extrusive Igneous via rapid cooling of gas-rich lava (Lava Stone)
About This Crystal
A single polished, translucent deep purple Amethyst bead flanked by multiple matte, opaque, black, highly porous Lava Stone beads with visible vesicular texture (pitting).
Physical Characteristics
Amethyst: Purple, vitreous luster, conchoidal fracture. Lava Stone: Black, dull/matte luster, high porosity, lightweight, abrasive texture.
Optical Properties
Amethyst: Refractive Index ~1.544-1.553, doubly refractive, weak pleochroism. Lava Stone: Opaque, no specific optical phenomena.
Hardness & Durability
Origin Region
Brazil, Uruguay, and Madagascar (Amethyst); Iceland, Hawaii, and Italy (Lava Stone volcanic regions)
Hardness & Durability
Amethyst: Mohs 7 (Durable); Lava Stone: Mohs 5 to 5.5 (Brittle, susceptible to crumbling if struck).
Care & Maintenance
Wash with warm soapy water. Avoid ultrasonic cleaners for the Lava Stone due to porosity. Amethyst may fade in prolonged direct sunlight.
Rarity & Value
Very Common. Affordable price range. Amethyst is often heat-treated to change color; Lava Stone is rarely treated but often used as an essential oil diffuser.
Special Characteristics
Lava Stone is highly vesicular (trapped gas bubbles) and porous. Amethyst shows characteristic color zoning and potential phantom inclusions.
Lore & History
Amethyst has been used since Ancient Greece to prevent intoxication; associated with the Crown Chakra. Lava Stone is used in modern practices as a grounding stone and diffuser for aromatherapy.