سلیکیت ها

سلیکیت ها



فلسپارها:

 این ها سلیکیت های پیچیده المونیم همرای پوتاش است،‌ سودا و آهک وافر ترین در سنگ های اذری هستند. فلسپار پوتاش که اورتوکلاز نیز یاد میشود، معمول ترین نوع است. رنگ آن سفید،‌ خاکی یا گلابی،‌ دارای جلای شیشیه یی میباشد. در اثر هوازدگی از خود، سلیکیت آب زده المونیم بنام کاولین یا خاک رس چین،‌ بجا میگذارد. سودا و آهک فلسپار بنام پلاجیوکلاز یاد میشود. اینها هم بهمین شکل فرسوده و تجزیه میشوند. فلسپارهای پلاجیوکلاز در بیشتر سنگ های آذرین مخصوصاً گونه های تاریکتر آن غنی از آهک میباشد. (وزن مخصوص = ۲.۶؛ درجه سختی = ۶).

میکا:‌

 گونه سفید آن بنام مسکوفایت (سلیکیت المونیم و پوتاشیم) و گونه سیا بنام میکا سیا یا بیوتایت (سلیکیت المونیم،‌ آهن و مگنیزیم). میکا به آسانی با ناخن انگشت خراشیده میشود، وخط شکستگی آشکارا دارد. میکا تشکیل دهنده معمول سنگ های آذرین و شیست متبلور میباشد (وزن مخصوص = ۲.۷ تا ۳.۱؛ درجه سختی = ۲.۵).

هرن بلند (امفیبول سیاه) و آژیت:

 منرال های پیچیده سلیکیت کلسیم، مگنیزیم، آهن میباشند. هر دو این ها سیاه مایل به سبز میباشند. هرن بلند بنام امفیبول نیز یاد میشود.  نسبتا کانی تاریک،‌ سیاه است که بلور شش پهلو را میسازد، در بیشتر سنگ های آذری یافت میشود دارای وزن مخصوص = ۳ تا ۳.۵ ؛ درجه سختی = ۵ تا ۶ را دارا است. آٰژیت (بنام پایروکسین نیز یاد میشود) سیاه مگر روشنتر از هرن بلند، تشکیل بلور های مونوکلینیک را میدهد،‌ در بیشتر سنگ های اساسی آذرین یافت میشوند. اغلباً سبب تغییرات در کلورایت میشود. وزن مخصوص = ۳ تا ۳.۵ ؛ درجه سختی آن ۵ تا ۶ میباشد.

اولوین (پریودایت نیز یاد میشود):

 سلیکیت مگنیزیم و آهن در سنگ های آذرین پایه مانند دلورایت،‌ باسالت و پریودوت یافت میشود. سبزرنگ و همانند کوارتز است (وزن مخصوص = ۳.۲ تا ۴ درجه سختی = ۶ تا ۷).
کانی های فوقی که  آهن و مگنیزیم دارا هستند، بنام کانی های فیرو-مگنیزیم یاد میشود و عموما در سنگ های پایه آذری (باسالت، دلورایت وغیره) به فراوانی یافت میشود.

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