{"product_id":"grape-agate-quartz-var-amethyst-mamuju-regency-west-sulawesi-province-indonesia-copy-4","title":"Grape Agate (Quartz var. Amethyst)- Mamuju Regency, West Sulawesi Province, Indonesia","description":"\u003cp class=\"PDq2pG_selectionAnchorContainer\"\u003e\u003cstrong\u003eGrape Agate (Quartz var. Amethyst)\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eMamuju Regency, West Sulawesi Province, Indonesia\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eDimensions:\u003c\/strong\u003e 3.4 x 3.2 x 2.4 cm\u003cspan class=\"PDq2pG_selectionAnchor\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eThis is the exact specimen you will receive.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eOften marketed under the trade name \u003cstrong\u003e“Grape Agate,”\u003c\/strong\u003e this remarkable material from Mamuju, West Sulawesi, Indonesia is more accurately described mineralogically as \u003cstrong\u003eamethystine quartz\u003c\/strong\u003e. Its distinctive grape-like spheres are composed of radially arranged quartz, creating the unusual botryoidal habit that has made this material highly sought after by collectors.\u003c\/p\u003e\n\u003cp\u003eThe terminology surrounding Grape Agate has been the subject of published gemological research. Laurs and Rossman (2018) examined Mamuju material and identified the grape-like aggregates as quartz rather than true agate. Subsequent Raman spectroscopy research likewise identified the material as quartz and found no detectable moganite in the samples examined, further supporting its classification as crystalline quartz rather than chalcedony (Štubňa, 2021).\u003c\/p\u003e\n\u003cp\u003eThe result is one of quartz's most unusual natural forms: tightly packed spheres of purple amethystine quartz that resemble a miniature cluster of grapes. Individual spheres may measure only a few millimeters across, creating a wonderfully intricate surface that rewards close inspection.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eMineralogical Note:\u003c\/strong\u003e Although \u003cstrong\u003e“Grape Agate”\u003c\/strong\u003e remains the established trade name and the term most commonly used by collectors, \u003cstrong\u003eamethystine quartz\u003c\/strong\u003e is a more mineralogically precise description of the purple Mamuju material examined in these studies.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eReferences\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eLaurs, B. M., \u0026amp; Rossman, G. R. (2018). Grape-like “Manakarra” quartz from Sulawesi, Indonesia. \u003cem\u003eThe Journal of Gemmology, 36\u003c\/em\u003e(2), 101–102.\u003c\/p\u003e\n\u003cp\u003eŠtubňa, J. (2021). Identification of “grape chalcedony” from Indonesia. \u003cem\u003eGemologický spravodajca, 1\u003c\/em\u003e(11), 5–10.\u003c\/p\u003e","brand":"The Crystalary","offers":[{"title":"Default Title","offer_id":47849766846595,"sku":"agate01-06","price":40.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0390\/4634\/8931\/files\/IMG_39362.jpg?v=1786487451","url":"https:\/\/www.thecrystalary.com\/products\/grape-agate-quartz-var-amethyst-mamuju-regency-west-sulawesi-province-indonesia-copy-4","provider":"The Crystalary","version":"1.0","type":"link"}