{"id":2189,"date":"2025-11-27T10:58:42","date_gmt":"2025-11-27T15:58:42","guid":{"rendered":"https:\/\/iversonsoftware.com\/wp\/?p=2189"},"modified":"2025-11-27T10:58:42","modified_gmt":"2025-11-27T15:58:42","slug":"achavalite","status":"publish","type":"post","link":"https:\/\/iversonsoftware.com\/wp\/achavalite\/","title":{"rendered":"Achavalite"},"content":{"rendered":"<p><!--StartFragment --><\/p>\n<p><strong>Achavalite is a rare selenide mineral, first discovered in Argentina in 1939, and remains notable for its unique chemistry, crystallography, and limited occurrence.<\/strong> It is a member of the nickeline group and is prized by mineralogists for its rarity and scientific significance.<\/p>\n<hr \/>\n<h2>\ud83c\udf0d Origins and Naming<\/h2>\n<p>Achavalite was discovered in the <strong>Cacheuta Mine, Sierra de Cacheuta, Mendoza Province, Argentina<\/strong>, in a selenium-rich deposit. The mineral was named in honor of <strong>Luis Ach\u00e1val (1870\u20131938)<\/strong>, a civil engineer and professor at the Universidad Nacional de C\u00f3rdoba.<\/p>\n<hr \/>\n<h2>\ud83d\udd2c Chemical and Structural Properties<\/h2>\n<ul>\n<li><strong>Formula:<\/strong> (Fe,Cu)Se (iron selenide with minor copper substitution)<\/li>\n<li><strong>Molecular Weight:<\/strong> ~134.81 g\/mol<\/li>\n<li><strong>Crystal System:<\/strong> Hexagonal, dihexagonal dipyramidal symmetry (space group P6\u2083\/mmc)<\/li>\n<li><strong>Unit Cell Dimensions:<\/strong> a = 3.636 \u00c5, c = 5.946 \u00c5, Z = 2<\/li>\n<li><strong>Color:<\/strong> Dark grey to black<\/li>\n<li><strong>Luster:<\/strong> Metallic to sub-metallic<\/li>\n<li><strong>Streak:<\/strong> Grey-black<\/li>\n<li><strong>Hardness:<\/strong> 2.5 on Mohs scale<\/li>\n<li><strong>Specific Gravity:<\/strong> ~6.53\u20136.58<\/li>\n<li><strong>Diaphaneity:<\/strong> Opaque<\/li>\n<\/ul>\n<p>Achavalite is structurally related to <strong>nickeline (NiAs)<\/strong> and belongs to the broader family of selenide minerals.<\/p>\n<hr \/>\n<h2>\u2699\ufe0f Geological Context<\/h2>\n<p>Achavalite forms under <strong>selenium-rich, low-sulfur reducing conditions<\/strong>, typically in hydrothermal veins. It is often associated with:<\/p>\n<ul>\n<li>Native selenium<\/li>\n<li>Other selenides such as ferroselite (FeSe\u2082) and trogtalite (CoSe\u2082)<\/li>\n<li>Occasionally sulfides<\/li>\n<\/ul>\n<p>Its occurrence is extremely limited, with the <strong>Cacheuta Mine<\/strong> being the only confirmed locality worldwide.<\/p>\n<hr \/>\n<h2>\ud83d\udcd6 Scientific and Historical Significance<\/h2>\n<ul>\n<li><strong>Mineralogical Rarity:<\/strong> Achavalite is considered a \u201cgrandfathered\u201d IMA mineral species, recognized before modern classification standards.<\/li>\n<li><strong>Research Value:<\/strong> Provides insight into selenium geochemistry and the stability of selenide phases in hydrothermal systems.<\/li>\n<li><strong>Historical Note:<\/strong> Its naming reflects Argentina\u2019s contributions to mineralogy in the early 20th century.<\/li>\n<\/ul>\n<hr \/>\n<h2>\u26a0\ufe0f Safety Considerations<\/h2>\n<p>Like many selenium-bearing minerals, Achavalite should be handled with care. Selenium compounds can be toxic if ingested or inhaled, so specimens are primarily of <strong>scientific and collector interest<\/strong>, not for decorative or jewelry use.<\/p>\n<hr \/>\n<h2>\u2728 Conclusion<\/h2>\n<p>Achavalite is a <strong>rare, selenium-rich mineral<\/strong> with distinctive hexagonal crystallography and metallic luster. Its discovery in Argentina highlights the geological diversity of the region and underscores the importance of selenium minerals in understanding hydrothermal systems. While not widely known, Achavalite remains a mineralogical curiosity, valued for its rarity, scientific insights, and historical significance.<\/p>\n<hr \/>\n<p><strong>In short: Achavalite is a rare selenium mineral from Argentina, notable for its hexagonal structure, metallic luster, and scientific importance.<\/strong><\/p>\n<p><!--EndFragment --><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Achavalite is a rare selenide mineral, first discovered in Argentina in 1939, and remains notable for its unique chemistry, crystallography, and limited occurrence. It is a member of the nickeline group and is prized by mineralogists for its rarity and scientific significance. \ud83c\udf0d Origins and Naming Achavalite was discovered in the Cacheuta Mine, Sierra de &hellip; <a href=\"https:\/\/iversonsoftware.com\/wp\/achavalite\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Achavalite&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2189","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/posts\/2189","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/comments?post=2189"}],"version-history":[{"count":1,"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/posts\/2189\/revisions"}],"predecessor-version":[{"id":2190,"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/posts\/2189\/revisions\/2190"}],"wp:attachment":[{"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/media?parent=2189"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/categories?post=2189"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/iversonsoftware.com\/wp\/wp-json\/wp\/v2\/tags?post=2189"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}