{"product_id":"large-black-mica-rough-freeform-specimen-150mm-1-45kg","title":"Large Black Mica Rough Freeform Specimen - 150mm, 1.45Kg","description":"\u003cp\u003e\u003cstrong\u003eThe piece pictured is what you'll receive\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch4\u003eLarge Black Mica Rough Freeform Specimen – 150mm, 1.45kg\u003c\/h4\u003e\n\u003cp\u003eA commanding display piece, this large rough freeform black mica specimen measures approximately 150mm and weighs a substantial 1.45kg. Its deeply lustrous, layered surfaces catch the light with an almost metallic shimmer, making it an impressive addition to any mineral collection, shelf display, or study. The natural freeform shape preserves the raw character of the material exactly as it formed within the earth.\u003c\/p\u003e\n\u003ch4\u003ePhysical Properties\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBlack Mica (Biotite)\u003c\/strong\u003e — Chemical formula: K(Mg,Fe)₃(AlSi₃O₁₀)(OH)₂ | Hardness: 2.5–3 Mohs | Crystal system: Monoclinic | Lustre: Vitreous to submetallic | Transparency: Opaque to subtranslucent on thin edges | Colour: Deep black to dark brown-black\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003eGeology \u0026amp; Formation\u003c\/h4\u003e\n\u003cp\u003eBiotite mica forms as a primary mineral in igneous rocks such as granite and diorite, as well as in metamorphic rocks including schist and gneiss. It crystallises during the cooling of magma or under high-pressure, high-temperature metamorphic conditions, often growing in distinctive book-like or platy masses. The black colouration results from elevated iron and magnesium content within its layered silicate structure. Large, well-defined specimens of this size are typically sourced from pegmatite intrusions, where slow cooling allows crystals to grow to impressive dimensions.\u003c\/p\u003e\n\u003ch4\u003eCrystal Properties\u003c\/h4\u003e\n\u003cp\u003eBlack mica is associated with grounding, protection, and energetic shielding. It is said to help deflect negativity, support emotional resilience, and anchor scattered energy — making it a valued stone for those seeking stability and clarity amid change. Its reflective surfaces are also linked to self-reflection and inner truth.\u003c\/p\u003e\n\u003ch4\u003eSpecimen Details\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 1.45kg\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize:\u003c\/strong\u003e Approximately 150 x 89 x 75mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Rough freeform specimen\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMineral:\u003c\/strong\u003e Black Mica (Biotite)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOrigin:\u003c\/strong\u003e Brazil\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"The Rock \u0026 Fossil Shop","offers":[{"title":"Default Title","offer_id":54680583242061,"sku":"XBANP","price":35.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0982\/0120\/7117\/files\/Black_Mica_Rough_Freeform_150mm_1_XBANP.jpg?v=1788805662","url":"https:\/\/www.rockandfossilshop.co.uk\/products\/large-black-mica-rough-freeform-specimen-150mm-1-45kg","provider":"The Rock \u0026 Fossil Shop","version":"1.0","type":"link"}