Shetland Agate (Epimorph/Pseudomorph type)
Quartz var. Agate (Pseudomorph after Calcite or Baryte) · Semi-Precious Gemstone / Collector Mineral
Crystal System
Trigonal / Microcrystalline; Habit is typically massive or banded, but this specimen shows a 'herringbone' or 'lattice' pseudomorph habit.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with trace inclusions of Manganese and Iron
Formation Process
Hydrothermal/Secondary: Quartz-rich fluids precipitate into cavities, often replacing or coating previous bladed minerals like calcite or baryte, leaving 'epimorph' impressions or lattices.
About This Crystal
A polished tower or point showing a grey-white to tan color. It features a distinct 'lattice' or 'herringbone' pattern caused by replacement of bladed crystals. It contains a prominent vug or geode cavity lined with tiny drusy quartz crystals. The luster is waxy to vitreous.
Physical Characteristics
Color: Grey, tan, cream; Streak: White; Fracture: Conchoidal; Specific Gravity: 2.6 – 2.65; Fluorescence: Often inert or weak yellow/green under UV.
Optical Properties
Refractive Index: 1.544 – 1.553; Birefringence: +0.009; Optical Character: Uniaxial; Transparency: Translucent to opaque.
Hardness & Durability
Origin Region
Shetland Islands, Scotland (particularly Burn of Da Water); also found in parts of Morocco and Poland.
Hardness & Durability
Mohs Hardness: 6.5 – 7; Toughness: Excellent; Stability: Very high, though direct heat should be avoided as it can cause cracking.
Care & Maintenance
Clean with warm soapy water and a soft brush. Safe for ultrasonic cleaners if no significant fractures are present. Store away from harder gems like Topaz or Diamond to prevent scratching.
Rarity & Value
Uncommon; Specific 'lattice' agate patterns are highly sought after by collectors. Value depends on the clarity of the pseudomorph patterns and the aesthetic of internal drusy vugs.
Special Characteristics
Features 'lattice' pseudomorphing/epimorphing where quartz has grown over bladed minerals. Includes a visible central drusy quartz geode pocket.
Lore & History
Historically, Scottish agates were highly prized during the Victorian era for 'Pebble Jewelry.' Metaphysically, it is associated with stability, grounding, and the uncovering of hidden information due to its complex internal layers.