Lace Agate
Chalcedony var. Agate · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal symmetry; Microcrystalline (Cryptocrystalline) aggregate with no visible external crystal faces
Mineral Group
Silicates; Tectosilicate subgroup (Quartz group)
Chemical Formula
SiO2 (Silicon Dioxide) with trace iron and aluminum impurities
Formation Process
Hydrothermal; formed by the deposition of silica from groundwater in the cavities (vesicles) of volcanic igneous rocks
About This Crystal
A pale, grayish-white to light-blue translucent specimen. It displays an opaque to translucent density with a waxy to vitreous luster. This small polished shard shows subtle banding characteristic of agate varieties.
Physical Characteristics
Color: Grayish-white; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.60-2.65; Fluorescence: Often inert but can show weak yellow-green under UV.
Optical Properties
Refractive Index: 1.530-1.543; Birefringence: Up to 0.004; Pleochroism: None; Dispersion: Low; Optical Character: Aggregates are typically Biaxial positive.
Hardness & Durability
Origin Region
Notably Chihuahua, Mexico (Blue Lace Agate) and various volcanic regions globally
Hardness & Durability
Mohs Hardness: 6.5 to 7; Toughness: Very high due to microcrystalline structure; Stability: Stable but sensitive to hydrofluoric acid.
Care & Maintenance
Safe to clean with warm soapy water and soft brushes. Generally resistant to sunlight fading, but avoid harsh chemicals and store away from harder stones like Sapphire or Diamond.
Rarity & Value
Common; Value is determined by the complexity of banding patterns and color saturation. Shards and small tumbled stones are very affordable, typically $1-$5.
Special Characteristics
Microcrystalline banding (chalcedonic layers) and potential for translucency when held to light. Displays high resistance to impact compared to macrocrystalline quartz.
Lore & History
Historically used for amulets and hardstone carving since the Neolithic era. In traditional lore, it is associated with calming the mind, improving articulation, and the throat chakra.