Mineral/Rock/Fossil Lab
Your ultimate objectives… are to be able to 1) tell whether a sample is a rock, mineral, or fossil, then 2) identify by name any of these samples you are given.
Come to the lab anytime it’s open to review the specimens. If there is another class in session, work at the table in the back of the room.
I. Minerals
Minerals are the building blocks for the rock material composing the earth’s lithosphere. They have a specific chemical composition and are identifiable by several properties.
Objective…
Given one of the minerals, make a positive identification by examining its properties. You may do any of the tests below to help you identify. You may also use your (and only yours) MINERAL DATA CHART during the exam.
Materials and Methods…
Using the designated mineral specimens, determine the properties for each. (Remember, you may not have to do every test on every sample.) Note that for each type of mineral there may be a range of colors, sizes, etc. in one container. Don't worry about the extreme samples. Concentrate on what appears to be the "typical" properties. Be sure to keep the specimens in the right container.
Color
Give a descriptive color for the mineral that will help you identify it later. (ex - chocolate brown with lighter streaks)
Streak
Scrape the sample carefully on a streak plate and give a descriptive color for the streak.
Luster
This is the way the surface looks or feels. Is the luster METALLIC, EARTHY, GLASSY, etc.? There are no right-or-wrong terms for this—use descriptions that are meaningful to you.
Fracture/Crystal
This is the way the mineral breaks (don’t break them any more) leaving certain surface features or definite crystal shapes. Use the crystal sample set to help you. If there is no obvious crystal then choose one of the following fractures: CONCHOIDIAL, SPLINTERED, FACETED, IRREGULAR
Hardness
Perform a Mohs test and estimate the hardness. This may be useful in differentiated very similar minerals.
Other Properties
Magnetism – Does a magnet attract the sample?
Acid test – Hydrochloric acid fizzes when applied to calcium-containing minerals, such as calcite and marble. Caution- Acid burns skin and eyes. Wash the acid off the sample when you finish and dry it.
Fluorescence – Place the mineral under a UV lamp (blacklight). Some minerals glow in different, but predictable colors.
Remember… I won’t grade your data chart or your ability to perform mineral tests. All you have to do is tell me what the mineral is. Use the properties to help you identify the samples.
II. Rocks
Objective: Be able to identify the following rocks by name, rock type, and other descriptors as noted. You may use the ROCK DATA SHEET to help you study, but you may not use it during the exam.
IGNEOUS TYPE (be able to distinguish aphanitic, phaneritic, etc.)
granite
rhyolite
obsidian
pumice
gabbro
basalt
SEDIMENTARY TYPE
sandstone
limestone
conglomerate
breccia
coal
shale
stalagmite
METAMORPHIC TYPE (be able to tell which rock these were metamorphized from)
gneiss
shist
marble
quartzite
slate
III. Fossils
Fossils are the evidences of living organisms that have been preserved in sedimentary rock. They may be the mineralized remains of the organism or parts of the organism, or artifacts made by the organism, such as foot prints or full body prints. For the following fossil samples, be able to identify the fossil by name and tell the information cited.
Crinoids
These were relatives of starfish, living on the floors of shallow seas. Fossil remains resemble rolls of Life-Savers candy, usually with a 5-pointed hole. The animal consisted of a holdfast, or pedestal that was attached to the ocean floor, with a slender stem growing upward. At the top of the stem there was a “head” that resembled a modern starfish. The center of this head looks like a 5-sided acorn.
In these samples you will see stem sections, loose stem circles, heads, holdfasts (large spheres), and whole specimens (display case #5, bottom shelf).
Petrified Wood
This is what remains when all of the wood molecules in a chunk of ancient wood are replaced by mineral crystals. The result is a precise copy of the original chunk, only in stone. Often, you can see the prints of the grain and wood fibers clearly.
Bryozoans
These were colonial animals, meaning that they lived as a cluster. They secreted a calcium-based pedestal to live on, similar to corals. The fossils seen here are the pedestals.
Trilobites
Trilobites are a common, and popular fossil for collectors. All trilobite species are extinct. The closest living relative of trilobites is the horseshoe crab. For whole specimens, see display case #2 and #5.
Ammonites
Although this shell fossil looks like a snail shell, it actually belonged to an animal that was more like an octopus. Similar to modern nautiluses, ammonites floated upright with their tentacles extended from the shell.
Brachiopods
These animals were similar to modern clams and oysters except that they are symmetrical from side to side rather than top to bottom. Brachiopods were sessile, meaning that they spent their life attached to something. There are a few species of living brachiopods, but the ones seen here are all extinct.
Pelecypods
This is a general term for bivalve, or 2-shell animals, such as clams, oysters, and mussels. The name mean “axe foot” because of the shape of its soft parts. Compare these to the brachiopods and note the symmetry difference.
Gastropods
This is a general term for univalve, or 1-shell animals, such as snails. The name means “stomach foot” since the animal typically stuck its belly out of the shell to move around.
Worm Tubes
These fossils are actually the sediments that hardened inside of empty worm holes in the sea floor.
Dinosaurs
Most of what remains of this most famous extinct animal group is bones. The reddish samples are from a Mosasaur. The black samples are from a cat-sized dinosaur called Captorhinus. Both samples were recovered in Oklahoma. Also, look at the joint-bone in display case #1 outside of lab.
We tend to focus on the large dinosaurs like T. Rex, when most species that we know were small like Captorhinus.
Corals
Like the bryozoans, coral animals secreted and formed their own base to sit on. Living species today form the large reefs that are found in much of the ocean. Reefs provide habitat for many other types of ocean life. The specimens you see here are extinct forms.
Ferns
These are well-preserved fern leaves in slate rock. They were found associated with a coal vein in eastern Oklahoma.
(You may use this sheet during the exam) / ______
Mineral / Color / Streak / Hardness / Crystal/ Fracture / Luster / Other
amphibole
apatite
azurite
biotite
calcite
carnatite
chalcopyrite
feldspar
fluorite
galena
graphite
gypsum
halite
hematite
magnetite
malachite
muscovite
olivine
plagioclase
pyrite
pyroxine
quartz
sulfur
talc
ROCK DATA CHART
(You may NOT use this sheet during the exam)
IGNEOUS / crystal type / other comments
granite / phaneritic
rhyolite
obsidian
pumice
gabbro
basalt
SEDIMENTARY
sandstone
limestone
conglomerate
breccia
coal
shale
stalagmite
METAMORPHIC / derived from… (we’ll cover this in class)
gneiss
shist
marble
quartzite
slate