Presentation is loading. Please wait.

Presentation is loading. Please wait.

Minerals under the microscope. The MINERALS you need to know quartz microcline plagioclase muscovite biotite amphibole pyroxene olivine garnet calcite.

Similar presentations


Presentation on theme: "Minerals under the microscope. The MINERALS you need to know quartz microcline plagioclase muscovite biotite amphibole pyroxene olivine garnet calcite."— Presentation transcript:

1 Minerals under the microscope

2 The MINERALS you need to know quartz microcline plagioclase muscovite biotite amphibole pyroxene olivine garnet calcite

3 Quartz grains in sandstone XPLPPL quartz

4 Plagioclase with repeated twinning XPLPPL plagioclase

5 Microcline grain in centre showing its distinctive cross- hatched twinning XPLPPL microcline

6 Muscovite clear under PPL but with perfect cleavage and bright interference colours XPLPPL muscovite PPLXPL

7 Biotite pleochroic with one perfect cleavage; strong natural colour masks polarisation colours making look greenish under XPL XPL PPL : lower view rotated to show pleochroism biotite feldspar

8 Amphibole pleochroic with 2 cleavages at 60 o or 120 o distinguishing it from biotite or pyroxene XPL PPL : lower view showing pleochroism amphibole

9 Pyroxene well-formed crystal seen here with 2 cleavages at 90 o : brightly coloured under XPL XPLPPL pyroxene pyroxene enlarged

10 Olivine looks like a stained-glass window; bright interference colours and thick black fractures PPLXPL olivine plagioclase

11 XPLPPL Garnet rounded crystal, transparent under PPL but goes extinct under XPL garnet

12 XPLPPL Calcite may show both high and low relief, transparent under PPL with 2 perfect cleavages at 120 o. Under XPL it shows pearly shades calcite


Download ppt "Minerals under the microscope. The MINERALS you need to know quartz microcline plagioclase muscovite biotite amphibole pyroxene olivine garnet calcite."

Similar presentations


Ads by Google