{"id":3504,"date":"2026-10-15T16:56:07","date_gmt":"2026-10-15T08:56:07","guid":{"rendered":"https:\/\/jtlcnc.com\/?p=3504"},"modified":"2026-10-15T16:56:09","modified_gmt":"2026-10-15T08:56:09","slug":"the-structure-of-granite-2","status":"publish","type":"post","link":"https:\/\/jtlcnc.com\/es\/2026\/10\/15\/the-structure-of-granite-2\/","title":{"rendered":"La estructura del granito"},"content":{"rendered":"

Granite is an acidic plutonic intrusive igneous rock<\/strong>. The magma cools and crystallizes slowly deep in the Earth’s crust, forming a holocrystalline granitic texture<\/strong>, which macroscopically appears as a massive structure<\/strong>.<\/p>\n\n\n\n

I. Mineral Composition (Microscopic Framework)
Three main minerals:<\/p>\n\n\n\n

    \n
  1. Quartz (20\u201340%, Mohs 7)<\/strong>: Anhedral grains, highest hardness, the core of wear resistance;<\/li>\n\n\n\n
  2. Potassium Feldspar Plagioclase (Total feldspar ~60%)<\/strong>: Subhedral tabular grains, the rock framework;<\/li>\n\n\n\n
  3. Dark Minerals (<10%)<\/strong>: Biotite, hornblende. Platy mica is the weak phase<\/strong>; high content reduces stability and causes water absorption creep. For high-precision platforms, mica content must be strictly controlled.
    Accessory minerals: Apatite, zircon, magnetite, etc. (trace amounts).<\/li>\n<\/ol>\n\n\n\n

    Jinan Blue (material for precision 000-grade platforms) strictly belongs to gabbro (commonly called black granite). Its minerals are pyroxene basic plagioclase<\/strong>, extremely fine-grained, dense and uniform, almost free of platy mica, with extremely low internal stress and thermal stability far superior to ordinary granite.<\/p>\n\n\n\n

    II. Rock Structure (Microscopic structure, Granite texture)
    Granitic texture (subhedral granular mosaic structure) \u2014 the signature structure of granite<\/strong>:<\/p>\n\n\n\n

      \n
    • Crystallization sequence: Accessory minerals \u2192 Dark minerals \u2192 Plagioclase \u2192 Potassium feldspar \u2192 Quartz;<\/li>\n\n\n\n
    • Dark minerals and plagioclase crystals are relatively complete (subhedral); quartz crystallizes last, filling the gaps, appearing as irregular anhedral grains;<\/li>\n\n\n\n
    • All mineral grains are tightly interlocked<\/strong>, locked together by crystallization forces rather than simple cementation. This is the root cause of granite’s high compressive strength and good rigidity…<\/li>\n<\/ul>\n\n\n\n

      Subtypes:<\/p>\n\n\n\n

        \n
      1. Equigranular structure<\/strong>: Uniform grain size. Fine-grained \/ medium-grained equigranular granite is most suitable for precision bases<\/strong>, offering uniform material and good deformation consistency;<\/li>\n\n\n\n
      2. Porphyritic-like structure<\/strong>: Large feldspar grains (phenocrysts) embedded in a fine-grained matrix; large thermal expansion difference between phenocrysts and matrix makes it unsuitable for 00\/000-grade high-precision platforms<\/strong>, as microcracks easily form under temperature differences;<\/li>\n\n\n\n
      3. Secondary microscopic structures: Striated feldspar structure, worm structure (intergrowth of quartz and feldspar).<\/li>\n<\/ol>\n\n\n\n

        III. Texture (Macroscopic organization)<\/p>\n\n\n\n

          \n
        1. Massive structure (Most common)<\/strong>: Minerals are randomly arranged, uniformly isotropic, the first choice for precision platforms;<\/li>\n\n\n\n
        2. Gneissose structure: Minerals are oriented, anisotropic in mechanical and thermal properties, cannot be used for high-precision reference platforms<\/strong>;<\/li>\n\n\n\n
        3. Flow structure: Rare, caused by magma flow.<\/li>\n<\/ol>\n\n\n\n

          IV. Internal Defects (Key focus for precision parts)
          Natural granite contains:
          Intercrystalline microcracks<\/strong>: Tiny gaps at mineral grain boundaries, the source of water absorption and micro-deformation; high-quality materials must have minimal microcracks;
          Primary pores<\/strong>;
          Alteration zones<\/strong>: Feldspar alters into clay, drastically reducing strength and stability;<\/p>\n\n\n\n

          The core of selecting high-end granite platforms is to filter out materials with many phenocrysts, mica enrichment, alteration, and dense microcracks. After machining, pore sealing and impregnation<\/strong> are performed to seal intercrystalline micropores, reduce water absorption, and minimize moisture-induced deformation.<\/p>\n\n\n\n

          V. Engineering Characteristics Derived from Structure (Useful for foreign trade \/ technical communication)
          \u2705 Advantages: Interlocked minerals \u2192 high rigidity, high compressive strength; fine-grained and dense \u2192 low coefficient of linear expansion; no plastic deformation, non-magnetic, corrosion-resistant.
          \u26a0oarse-grained structure; rapid cooling or magma mixing can lead to<\/p>\n\n\n\n

          \"\"<\/figure>","protected":false},"excerpt":{"rendered":"

          Granite is an acidic plutonic intrusive igneous rock. The magma cools and crystallizes slowly deep in the Earth’s crust, forming a holocrystalline granitic texture, which macroscopically appears as a massive structure. I. Mineral Composition (Microscopic Framework)Three main minerals: Jinan Blue (material for precision 000-grade platforms) strictly belongs to gabbro (commonly called black granite). Its minerals…<\/p>","protected":false},"author":1,"featured_media":2382,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"categories":[35],"tags":[],"class_list":["post-3504","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"taxonomy_info":{"category":[{"value":35,"label":"NEWS"}]},"featured_image_src_large":["https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/04\/\u5fae\u4fe1\u56fe\u7247_20260407144905_12_11-1-1024x768.jpg",1024,768,true],"author_info":{"display_name":"jinxing6611@gmail.com","author_link":"https:\/\/jtlcnc.com\/es\/author\/jtlcnc\/"},"comment_info":0,"category_info":[{"term_id":35,"name":"NEWS","slug":"news","term_group":0,"term_taxonomy_id":35,"taxonomy":"category","description":"","parent":0,"count":405,"filter":"raw","cat_ID":35,"category_count":405,"category_description":"","cat_name":"NEWS","category_nicename":"news","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/posts\/3504","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/comments?post=3504"}],"version-history":[{"count":1,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/posts\/3504\/revisions"}],"predecessor-version":[{"id":3505,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/posts\/3504\/revisions\/3505"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/media\/2382"}],"wp:attachment":[{"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/media?parent=3504"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/categories?post=3504"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jtlcnc.com\/es\/wp-json\/wp\/v2\/tags?post=3504"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}