This exceptional tenebrescent cubic fluorite specimen comes from the famous Hidden Forest Pocket of the Diana Maria Mine in Weardale, England. The sharply formed cubes display a remarkable color-changing effect—shifting from vivid forest green to deep blue depending on lighting conditions. The specimen features crisp cubic fluorite crystals perched on matrix with smaller secondary crystals, giving it a balanced cabinet display aesthetic.
Weardale fluorites are among the most celebrated fluorites in the world, prized for their vivid color zoning, daylight fluorescence, and exceptional crystal form.
This rare pocket material is highly sought after by collectors due to its limited production and unique optical properties.
Highlights
• Rare tenebrescent color-changing fluorite
• Color shift from green to blue depending on light exposure
• Sharp cubic fluorite crystal habit
• From the famous Hidden Forest Pocket
• Collected from the Diana Maria Mine, Weardale, England
• Exceptional collector specimen from a world-renowned fluorite locality
• Strong daylight and UV fluorescence typical of Weardale fluorite
• Attractive cluster composition with secondary crystals on matrix
• Cabinet specimen ideal for display or advanced mineral collections
Specifications
Mineral: Fluorite
Chemical Formula: CaF₂
Crystal System: Isometric (cubic)
Color: Forest green shifting to deep blue
Luster: Vitreous
Transparency: Transparent to translucent
Habit: Cubic crystals on matrix
Tenebrescence: Yes (color-changing)
Locality: Hidden Forest Pocket, Diana Maria Mine, Frosterley, Weardale, County Durham, England
Specimen Type: Cabinet mineral specimen
Dimensions can be found in product listing photos.
More Detailed Description
This stunning specimen showcases the extraordinary mineralogical beauty that the Northern Pennines fluorite district is famous for. The fluorite crystals grow in classic cubic formations with clean edges and glassy faces, creating a geometric display of natural perfection.
What makes this piece especially remarkable is its tenebrescent optical behavior—a property where the crystal color visibly shifts depending on lighting conditions. Under indoor lighting the fluorite appears a vibrant forest green, but when exposed to sunlight or UV light the cubes transform into rich blue hues, producing a dramatic and captivating visual effect.
The specimen originates from the Hidden Forest Pocket, a discovery known for producing fluorite crystals coated in calcite that concealed vivid green crystals underneath until preparation revealed them.
The composition is aesthetically balanced, with multiple cubic fluorite crystals clustered naturally across the matrix. Secondary crystals and subtle mineral inclusions add depth and texture while preserving the visual dominance of the fluorite cubes.
Specimens from this pocket are increasingly scarce and are quickly absorbed into private collections due to their rare optical properties and limited production.
Locality
Hidden Forest Pocket
Diana Maria Mine
Frosterley, Weardale
County Durham
England, United Kingdom
The Diana Maria Mine sits in the historic Weardale mining district, an area famous for producing some of the finest fluorite specimens in the world.
Geological Formation
The fluorite crystals formed in hydrothermal mineral veins associated with historic lead-zinc mineralization in the Northern Pennines ore field.
Mineral-rich fluids moved through fractures in the surrounding limestone and deposited fluorite crystals as they cooled. Over time these crystals grew into the sharply defined cubic forms seen in this specimen.
Mineralogy Information
Fluorite is a calcium fluoride halide mineral that crystallizes in the isometric crystal system and commonly forms cubes, octahedra, or combinations of both.
Trace elements and structural defects within the crystal lattice are responsible for fluorite’s wide range of colors and its fluorescent and tenebrescent properties.
Associated minerals in the Weardale district often include:
• Calcite
• Quartz
• Galena
• Barite
Key Features
• Rare tenebrescent fluorite crystals
• Dramatic green-to-blue color change
• Classic cubic crystal geometry
• From a famous UK fluorite locality
• Limited-production pocket material
• Highly aesthetic cabinet display specimen
Geological Era
Carboniferous Period
Approximately 300–330 million years ago, when mineralizing fluids circulated through the limestone formations of the Northern Pennines ore field.
Mineral Class
Halides
Rock Formation
Fluorite formed within hydrothermal veins cutting through Carboniferous limestone in the Northern Pennines lead-zinc mineral district.
Historical & Folklore Stories
The Weardale region has a mining history dating back to medieval times. The area became famous during the 18th and 19th centuries for its rich lead and fluorspar deposits, attracting miners from across England and Cornwall.
Fluorite from this region helped inspire the term “fluorescence”, because specimens from these mines glow brightly under ultraviolet light due to trace europium impurities.
Today, Weardale fluorite is considered among the finest collector fluorite specimens on Earth.
Why Collectors Love It
Collectors are drawn to this specimen for several reasons:
• Rare tenebrescent color change
• Classic cubic crystal form
• Historic and famous Weardale locality
• Limited production from the Hidden Forest Pocket
• Exceptional visual display quality
For fluorite collectors, pieces from the Diana Maria Mine represent modern classics in the mineral world.
Display & Care Instructions
Fluorite is a relatively soft mineral (Mohs hardness 4) and should be handled with care.
Display Tips:
• Keep in a stable display case
• Avoid prolonged direct sunlight to preserve color
• Use LED lighting to enhance crystal clarity
Cleaning:
• Dust gently with compressed air or a soft brush
• Avoid harsh chemicals or ultrasonic cleaners
Shipping & Handling
Your specimen will be professionally packed using collector-grade mineral packaging techniques to ensure safe transit.
• Carefully wrapped and padded
• Insured shipping included
• Tracking provided
• Ships within 1–2 business days
We treat every specimen as if it were going into our own collection.
A Metaphysical Nod
While metaphysical interpretations are belief-based and not scientific, fluorite has long been appreciated in spiritual traditions for its calming and clarifying energy.
Many believe fluorite can support:
• Mental clarity
• Emotional balance
• Focus and organization
• Protection from chaotic energies
Green fluorite is often associated with the Heart Chakra, encouraging growth, renewal, and harmony.
Suggested mantra:
“I allow clarity and balance to guide my thoughts and actions.”
Why Trust Wandering Stones
At Wandering Stones, we are passionate mineral collectors who believe in education, authenticity, and community.
When you purchase from us you can expect:
• Carefully sourced natural mineral specimens
• Accurate locality and mineral information
• Professional packaging and fast shipping
• Transparent and honest descriptions
• A trusted name among mineral collectors
We proudly bring you everything crystals, rocks, minerals, and geology—from the common to the ultra rare.
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