Welcome To Ashstone Exports LTD

  • Nigeria

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Welcome to Ashstone Exports LTD

At Ashstone Exports Ltd, we are committed to sustainability, ethical sourcing, and long-term growth. We exist to unlock Nigeria’s economic potential and deliver value to partners across continents. Our story is one of quality, integrity, and ambition—driven by a belief that Africa’s resources can fuel global industries.

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  • House 2 Amasom 18 Bishop Edward Benson street Ogudu GRA phase 2

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Tourmaline

Ashstone Exports Ltd

Tourmaline

Property Specification
Chemical Formula (Ca,K,Na)(Al,Fe,Li,Mg,Mn)₃(Al,Cr,Fe,V)₆(BO₃)₃(Si,Al)₆O₁₈(OH,F)₄
Crystal System Trigonal
Crystal Habit Prismatic, striated crystals
Color Black, brown, green, pink, red, blue, yellow, colorless (varies by type)
Luster Vitreous
Transparency Transparent to opaque
Hardness (Mohs) 7 to 7.5
Specific Gravity 2.9 to 3.3
Cleavage Indistinct
Fracture Conchoidal to uneven
Streak White
Refractive Index 1.614 to 1.666 (varies by variety)
Pleochroism Strong (colors vary depending on orientation)
Birefringence 0.014 to 0.040
Tenacity Brittle
Magnetism Some varieties may be weakly magnetic