{"id":207321,"date":"2025-04-21T13:28:28","date_gmt":"2025-04-21T13:28:28","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=207321"},"modified":"2025-04-21T13:28:31","modified_gmt":"2025-04-21T13:28:31","slug":"a-finely-crystalline-or-glassy-igneous-texture-indicates-that","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/04\/21\/a-finely-crystalline-or-glassy-igneous-texture-indicates-that\/","title":{"rendered":"A finely crystalline or glassy igneous texture indicates that"},"content":{"rendered":"\n

A finely crystalline or glassy igneous texture indicates that<\/p>\n\n\n\n

the rock cooled quickly.<\/p>\n\n\n\n

the rock cooled slowly.<\/p>\n\n\n\n

the rock broke apart as it flowed.<\/p>\n\n\n\n

there was a lot of gas in the magma.<\/p>\n\n\n\n

the ash and pumice were hot and became compacted.<\/p>\n\n\n\n

The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n

Correct Answer: The rock cooled quickly.<\/strong><\/p>\n\n\n\n

Explanation (300 words):<\/h3>\n\n\n\n

Igneous rocks are formed from the cooling and solidification of molten rock, either magma beneath the Earth\u2019s surface or lava on the surface. The texture of an igneous rock\u2014meaning the size, shape, and arrangement of its mineral crystals\u2014depends largely on the rate at which the magma or lava cools<\/strong>.<\/p>\n\n\n\n

A finely crystalline<\/strong> or glassy texture<\/strong> indicates rapid cooling<\/strong>. When lava erupts onto the surface (extrusive igneous activity), it loses heat very quickly to the atmosphere or ocean. This rapid cooling doesn\u2019t give the mineral crystals enough time to grow large, resulting in a fine-grained texture, where the crystals are so small they may be difficult to see without a microscope. Common rocks with this texture include basalt<\/strong> and andesite<\/strong>.<\/p>\n\n\n\n

If the cooling is extremely fast\u2014as in the case of lava that comes into contact with water or air instantly\u2014the rock may cool so quickly that no crystals can form at all<\/strong>, resulting in a glassy texture<\/strong>. An example of this is obsidian<\/strong>, which looks like black volcanic glass.<\/p>\n\n\n\n

In contrast, slow cooling<\/strong> allows large crystals to form and results in coarse-grained textures, typical of intrusive igneous rocks<\/strong> like granite.<\/p>\n\n\n\n

The other options in the question describe different processes:<\/p>\n\n\n\n

    \n
  • \u201cThe rock broke apart as it flowed\u201d refers more to mechanical processes, not crystallization.<\/li>\n\n\n\n
  • \u201cThere was a lot of gas in the magma\u201d results in vesicular textures<\/strong>, like in pumice or scoria, not glassy or fine-grained ones.<\/li>\n\n\n\n
  • \u201cThe ash and pumice were hot and became compacted\u201d describes pyroclastic<\/strong> processes, forming rocks like tuff\u2014not finely crystalline or glassy textures.<\/li>\n<\/ul>\n\n\n\n

    In summary, a finely crystalline or glassy texture in igneous rocks is a clear indication of quick cooling<\/strong>, often associated with volcanic (extrusive) environments.<\/p>\n\n\n\n

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

    A finely crystalline or glassy igneous texture indicates that the rock cooled quickly. the rock cooled slowly. the rock broke apart as it flowed. there was a lot of gas in the magma. the ash and pumice were hot and became compacted. The correct answer and explanation is : Correct Answer: The rock cooled quickly. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-207321","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/207321","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=207321"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/207321\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=207321"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=207321"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=207321"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}