After about six weeks end the experiment; write down the ending date, along with any final observations. What do you conclude? Which materials do you think manganese-oxidizing bacteria like best? What are your conclusions? Report an Emergency. Get in Touch. Site Map Non-Discrimination Policy. Large book crystals occur in pegmatites and it is widespread in other igneous and metamorphic rocks, while tiny detrital flakes may be found in dark sandstones. Characteristics: Glassy to pearly luster; hardness of 2.
Chromite is a chromium-iron oxide found in pods or veins in bodies of peridotite and serpentinite. Look for brown streaks. It may also be segregated in thin layers near the bottom of large plutons, or former bodies of magma, and is sometimes found in meteorites. It may resemble magnetite but rarely forms crystals and is only weakly magnetic. Characteristics: Submetallic luster; hardness of 5.
Hematite, an iron oxide, is the most common black or brownish-black mineral in sedimentary and low-grade metasedimentary rocks. It varies greatly in form and appearance, but all hematite produces a reddish streak. Characteristics: Dull to semimetallic luster; hardness of 1 to 6. Hornblende is the typical amphibole mineral in igneous and metamorphic rocks.
Look for glossy black or dark green crystals and cleavage fragments forming flattened prisms in cross-section corner angles of 56 and degrees. Crystals may be short or long, and even needle-like in amphibolite schists. Crystals of this titanium-oxide mineral are sprinkled in many igneous and metamorphic rocks, but they're sizeable only in pegmatites. Ilmenite is weakly magnetic and produces a black or brownish streak. Its color can range from dark brown to red.
Characteristics: Submetallic luster; hardness of 5 to 6. Magnetite or lodestone is a common accessory mineral in coarse-grained igneous rocks and metamorphic rocks. It may be gray-black or have a rusty coating.
Crystals are common, with striated faces shaped in octahedrons or dodecahedrons. Distinguishing Characteristics: dull, reddish- brown, very fine grains smooth to the touch , breaks easily. If an edge is dipped in water and drawn along a surface, shale will leave a muddy streak. Origin of your Samples: Aldershot, Ontario Uses: This shale is the raw material for the brick manufacturing industry in Ontario. Rock Type: metamorphic Composition: clay minerals Original Rock: shale Environment: Slate forms from the heat and pressure when shale is buried deep in the crust.
The depth of burial to make slate out of shale is about 10 km. Distinguishing Characteristics: dark grey to black, very fine grains smooth to the touch , harder than shale, distinct layers are visible. In the past, slate was used as chalkboards.
About Us. Indigenous Programs. School Programs. Outreach Programs. School Programs - Students. Field Trip Subsidy Application Procedures. Rock Identification Guide. Conglomerate Rock Type: sedimentary Composition: fragments of other rocks and minerals cemented by silica, calcite, or iron oxide. Distinguishing Characteristics: dark grey with imbedded fragments Origin of your Samples: Kirkland Lake, Ontario Uses: conglomerate is used in the construction industry Conglomerate samples courtesy of the Resident Geologist Program, Ontario Ministry of Northern Development and Mines.
Dolostone Rock Type : sedimentary Composition : dolomite and fossils Metamorphoses to : marble Environment : Sea water, high in magnesium, flows through porous limestone and replaces some of the calcium with magnesium turning limestone into dolostone.
Dolostone samples courtesy of Dufferin Aggregates, Milton Quarry. Gneiss Rock Type: metamorphic Composition: quartz, feldspar, mica Original Rock: granite, gabbro Environment: Gneiss forms at high temperatures and pressures. Limestone Rock Type: sedimentary Composition: mostly calcite Environment: There are several ways for limestone to form.
Limestone samples courtesy of Beachville Lime Ltd. Marble Rock Type : metamorphic Composition : very pure, recrystallized calcite Original Rock : limestone or dolostone Environment : Marble forms at many temperatures and pressures.
Quartzite Rock Type: metamorphic Composition: recrystallized quartz grains Original Rock: sandstone Environment: Quartzite forms at many temperatures and pressures. Quartzite samples courtesy of Unimin Canada Ltd. If the sediment is poor in organic matter or well oxygenated there may be enough oxygen to allow all of the organic matter to decay, via respiration by decomposers, and have oxygen left over to oxidize the iron.
Gray and black shales, and coal in the extreme case, indicate high organic matter and low oxygen in the sediments.
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