ROCK IDENTIFICATION LAB
What type of rock is this? Where or how is it formed?
Obsidian Extrusive Igneous Rock No crystals formed Glassy Very quick cooling molten rock (lava)
What type of rock is this? Where or how is it formed?
Basalt Extrusive Igneous Rock Fine grained (some small crystals) Formed from dark dense lava
What type of rock is this? Where or how is it formed?
Scoria Extrusive Igneous Rock No crystals formed Forms as a frothy crust on the top of a lava flow or as material ejected from a volcanic vent and solidifying while airborne Many holes formed - gasses released
What type of rock is this? Where or how is it formed?
Pumice Extrusive Igneous Rock No crystals formed Quick cooling molten rock (lava) Many holes formed - gasses released Floats on water
What type of rocks are these? Where or how are they formed?
Granite Intrusive Igneous Rock Coarse Grained - can see crystals Contains quartz and feldspar
What type of rock is this? Where or how is it formed?
Shale Sedimentary Rock Thin, dark gray sheets easily broken Formed from mud and clay being pressed together
What type of rock is this? Where or how is it formed? Image Source
Sandstone Sedimentary Rock Light red/dark pink with very small pieces of sand Quartz cemented by silica or lime Most form in shallow seas
What type of rock is this? Where or how is it formed? Image Source
Coal Organic Sedimentary Rock Most coal ( soft coal /bituminous) is sedimentary (typically has bright and dull bands) Hard coal (anthracite) is metamorphic (has a bright luster) Black, smooth and lightweight Formed from layers of plant remains that are pressed together over time
What type of rock is this? Where or how is it formed? Image Source
Limestone Organic Sedimentary Rock Calcium Carbonate - calcite Forms from the accumulation of shell, coral, and fecal debris in clear, warm, shallow marine waters
What type of rock is this? Where or how is it formed?
Conglomerate Sedimentary Rock Red with rounded pebbles cemented together Formed near moving water
What type of rock is this? Where or how is it formed?
Quartzite Metamorphic Rock Non-Foliated Individual quartz grains have recrystallized but are too small too see Metamorphism of Sandstone
What type of rock is this? Where or how is it formed?
Marble Metamorphic Non-Foliated Made of mostly small to medium sized calcite crystals Metamorphism of Limestone
What type of rock is this? Where or how is it formed?
Gneiss Metamorphic Foliated pink and grey alternating bands Medium to coarse grained texture Metamorphism of Granite
What type of rock is this? Where or how is it formed?
Slate Metamorphic Rock Foliated Breaks into thin slices Metamorphism of Shale
What type of rock is this?
Metamorphic (schist)
What type of rock is this?
Sedimentary (coquina limestone)
What type of rock is this?
Igneous (andesite)
Rock or Mineral?
Mineral (muscovite mica)
Rock or Mineral?
Hornfels Metamorphic Rock Non-foliated Fine grained crystals Metamorphism of clays or Shales
Comparisons Basalt vs. Slate Both dark colors Basalt is igneous and Slate is metamorphic Pumice vs. Basalt Both igneous made of quick cooling lava (extrusive) Pumice is felsic and Basalt is mafic Granite vs. Gneiss Both have course grains/crystals Granite is igneous and Gneiss is metamorphic
Comparisons Scoria vs. Pumice Both are porous (have air bubbles/holes) Scoria is mafic and Pumice is felsic Obsidian vs. Coal Both are black, no crystals Obsidian is igneous and Coal is sedimentary Marble vs. Limestone Both are made of calcite Marble is metamorphic and Limestone is sedimentary
Comparisons Slate vs. Shale Both thin slices, made of mud and clay, dark color Slate is metamorphic (morphed from shale), Shale is sedimentary Hornfels vs. Slate Both metamorphic rocks made from Shale Hornfels is not foliated and Slate is foliated Sandstone vs. Quartzite Both grainy and made of Quartz Sandstone is sedimentary and Quartzite is metamorphic
Comparisons Limestone vs. Marble Both are made of calcite Limestone is sedimentary and Marble is metamorphic Conglomerate vs. Limestone Both sedimentary rocks formed in or near water Conglomerate is clastic (made of pebbles cemented together by moving water) and Limestone is organic (made of shell coral, fecal debri found in shallow water) Gneiss vs. Granite Both contain course grain crystals Gneiss is metamorphic and Granite is igneous
Comparisons Quartzite vs. Sandstone Both contain the mineral Quartz Quartzite is metamorphic (pressure and heat), Sandstone is sedimentary (cemented together by water + sandstone or lime) Coal vs. Obsidian Both are black and smooth and contain no crystals Coal is sedimentary and Obsidian is igneous Shale vs. Slate Both made of mud and clay (Slate is made from Shale) Shale is sedimentary and Slate is metamorphic