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1 Markets I: The Ecosystem and Exchange-Traded Marketsবাজার অনলাইন 2 Markets II: Rates, FX and Creditবাজার অনলাইন 3 Markets III: Commodities, Energy and Cryptoবাজার অনলাইন 4 Quantitative Methodsপদ্ধতি অনলাইন 5 Derivatives and Volatilityডেরিভেটিভস অনলাইন 6 Rates, Credit, XVA and Riskসুদহার, ঋণ ও ঝুঁকি অনলাইন 7 Research Craft: Predictors, Backtests, Measurement, Portfoliosগবেষণা অনলাইন 8 Strategies I: Equities and Futuresকৌশল অনলাইন 9 Strategies II: Volatility, Relative Value, Macro and the Bank Desksকৌশল অনলাইন 10 Microstructure and Executionএক্সিকিউশন অনলাইন 11 Market Making and High-Frequency Tradingমার্কেট মেকিং অনলাইন 12 Machine Learning for Marketsমেশিন লার্নিং অনলাইন 13 Low-Latency Softwareপ্রযুক্তি অনলাইন 14 Networks, Hardware and Trading Infrastructureপ্রযুক্তি অনলাইন 15 Research, Data and Risk Platformsপ্রযুক্তি অনলাইন 16 The Desk and the Firmপ্রতিষ্ঠান অনলাইন 17 The Industry: Firms, Roles and Careersক্যারিয়ার অনলাইন 18 Interviews I: Maths, Probability and Speedক্যারিয়ার অনলাইন 19 Interviews II: Markets, Trading Games and the Final Roundক্যারিয়ার অনলাইন 20 Interviews III: Codeক্যারিয়ার অনলাইন
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Earth and Space Sciences · পরিভাষা

Thin section; polarising microscope কী?

অন্য নাম: thin section · polarising microscope

Definition 16.11 High School Earth and Space Sciences · অধ্যায় 16 — Minerals

A thin section is a slice of rock ground down to a thickness of 0.03 mm0.03\,\mathrm{mm} and mounted on a glass slide: at this thickness light passes through most minerals. A polarising microscope is a microscope fitted with two polarising filters, one below the slide and one above it. The section is seen in plane-polarised light with the lower filter only, and between crossed polars when the upper filter is added with its direction perpendicular to that of the lower one.

Left and centre: the same basalt in thin section, in plane-polarised light and between crossed polars. The rock is fine grained: small elongated crystals, mostly plagioclase, and black specks that let no light through in either view; between crossed polars the crystals light up in greys and colours. Photographs Chmee2 (CC BY-SA 3.0). Right: crystals of quartz in a granite, between crossed polars, each in its own shade of grey (the scale bar is 0.5\, mm). Photograph Michael C. Rygel (CC BY-SA 3.0). Left and centre: the same basalt in thin section, in plane-polarised light and between crossed polars. The rock is fine grained: small elongated crystals, mostly plagioclase, and black specks that let no light through in either view; between crossed polars the crystals light up in greys and colours. Photographs Chmee2 (CC BY-SA 3.0). Right: crystals of quartz in a granite, between crossed polars, each in its own shade of grey (the scale bar is 0.5\, mm). Photograph Michael C. Rygel (CC BY-SA 3.0). Left and centre: the same basalt in thin section, in plane-polarised light and between crossed polars. The rock is fine grained: small elongated crystals, mostly plagioclase, and black specks that let no light through in either view; between crossed polars the crystals light up in greys and colours. Photographs Chmee2 (CC BY-SA 3.0). Right: crystals of quartz in a granite, between crossed polars, each in its own shade of grey (the scale bar is 0.5\, mm). Photograph Michael C. Rygel (CC BY-SA 3.0).
Left and centre: the same basalt in thin section, in plane-polarised light and between crossed polars. The rock is fine grained: small elongated crystals, mostly plagioclase, and black specks that let no light through in either view; between crossed polars the crystals light up in greys and colours. Photographs Chmee2 (CC BY-SA 3.0). Right: crystals of quartz in a granite, between crossed polars, each in its own shade of grey (the scale bar is 0.5 mm0.5\,\mathrm{mm}). Photograph Michael C. Rygel (CC BY-SA 3.0).
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