Gems, Minerals, Crystals & Rocks–What's the Difference?
Gem, Mineral, Rock: What’s the Difference? Descriptive Transcript
[Drawings of rocks and gems scroll by on the screen. The American Museum of Natural History logo unfolds.]
[Text appears: What are minerals, rocks, crystals, and gems?]
NARRATOR: What are minerals, rocks, crystals, and gems?
[Text appears: What’s the difference?]
NARRATOR: What’s the difference? Well, to start off simply,
[Photos of a rough gray rock, a pink and white pointed crystal, and a blue gem set in gold appear.]
NARRATOR: rocks, crystals, and gems all can be made up of minerals.
[The photos converge to reveal the word “Minerals.” Question marks appear around the text.]
NARRATOR: So, what the heck is a mineral?
[The word “Minerals” becomes smaller and an octahedronal shape draws on screen. Behind, video of a mineral mine with excavated dirt underneath pine trees.]
NARRATOR: A mineral is a solid made by the natural activities of Earth,
[A cartoon volcano spews orange lava.]
NARRATOR: like lava spewing out of volcanoes
[The volcano disappears and is replaced by cartoon stalagtites and stalagmites with drips of water flowing down them.]
NARRATOR: or water dripping down through cracks in caves.
[Images of a purple fluorite, a slab of gold, and an orange diamond-shaped calcite appear on screen.]
NARRATOR: Fluorite, gold, and calcite are just a few mineral names you might recognize.
[The images disappear and the octahedronal mineral shape reappears. Next to it, circles with element symbols of “F” for fluorine and “Ca” for calcium pop up.]
NARRATOR: Minerals are made up of elements that come together in a regular, specific pattern.
[The element symbols multiply and converge into the shape of a three-dimensional cube. The elements disappear and only the drawing of the cube remains.]
NARRATOR: These geometric groups of elements are the building blocks of a mineral.
[More cubes stack next to and on top of the original cube. Then the image zooms out to show that this is a projection of the inside of the octohedron drawing shown earlier. Text appears: Crystal. A drawing of three spear-like cartoon crystals appears next to the text.]
NARRATOR: A crystal of that mineral forms when these building blocks stack on top of one another,
[The octahedron mineral tilts and joins an actual close up photo of fluorite crystals. Another large fluorite crystal appears, followed by a halite (salt) crystal formation made of many white squares.]
NARRATOR: repeating their arrangement to form a three-dimensional object with flat faces.
[Video of a sparkling quartz crystal. Text appears: Quartz.]
NARRATOR: Quartz, for example has a crystal structure
[Two circles with the element symbols of “O” for oxygen appear, followed by one “Si” circle for silicon. The chemical formula for quartz,SiO2, appears in text below.]
NARRATOR: made of oxygen atoms and silicon atoms
[The circles and chemical formula are replaced by a three-dimensional rhombus-like shape.]
NARRATOR: that repeat in a shape that looks like a rhombus.
[The rhombus is joined on screen by more three-dimensional drawings, most looking like variations of cubes and hexagonal prisms.]
NARRATOR: The shapes that these chemical building blocks take are different from mineral to mineral.
[Two circles appear on screen filled with “carbon atoms” represented by the letter “C.” Below the circle on the left, the text “diamond” appears and below the circle on the right the text “graphite” appears.]
NARRATOR: Sometimes, two minerals can be made of the same elements,
[The carbon atoms disappear. On the left, a cube tilted upwards to look like a diamond. On the right several two-dimensional hexagons stack on top of and next to each other as in sheets.]
NARRATOR: but with different building blocks making up their structure –
[In the circle on the left, a sparkling drawing of a gem. In the circle to the right, a drawing of a pencil.]
NARRATOR: like diamond and graphite.
[Video of different crystals appear, and drawn lines trace the geometric shapes that appear within them, and their flat faces.]
NARRATOR: The large geometric shapes and flat faces we see in crystals reflect what happens when these building blocks repeat over and over again.
[Video of a large rock on display at the Museum. The text “Rock” appears on screen next to a lumpy speckled drawing of a rock.]
NARRATOR: Now let’s move on to rocks. A rock is a solid object made up of mineral grains,
[A cartoon magnifying glass appears over the drawing of the rock and reveals a mashed-up group of differently colored and differently shaped geometric forms, which represent different minerals.]
NARRATOR: but it can have many different minerals inside it.
[We zoom out to see the lumpy drawing of the rock next to the pointed and flat-faced cartoon of a crystal.]
NARRATOR: And you don’t see the same repetitive shapes that you see in crystals.
[Video footage of a slab of pink granite. Text appears: “Granite”]
NARRATOR: Granite is an easy example –
[Circles draw on around different colors of different minerals found within this piece of granite.]
NARRATOR: you can see the different grains of many types of minerals making up a piece.
[Video of a small white chunk of limestone. Text appears: “Limestone.”]
NARRATOR: Limestone is also a rock, even though it’s usually made
[Circles draw around the limestone and converge with lines to text that appears above: “Calcite.”]
NARRATOR: of mostly one mineral, calcite.
[A split screen shows the same limestone on the left, and an orange calcite crystal on the right. Diamond shapes fall and crash together in a pile on the left, superimposed over the limestone.]
NARRATOR: But limestone is made of calcite fragments mashed all together,
[On the right, the lines and faces of the diamond-shaped calcite crystal are outlined.]
NARRATOR: and a calcite crystal has order and a geometric shape.
[A blue sparkling gem on a white background appears.]
NARRATOR: So where do gems fit in?
[Several red round- and square-shaped gems appear in a display. Lines outline their geometric shape.]
NARRATOR: They have a geometric shape,
[A split screen shows a green oblong gem on the right, and a green oblong crystal on the left. Lines appear to show their similarity in shape and form.]
NARRATOR: and many look like crystals, right?
[Text appears: “Gems” with a cartoon drawing of a cut gem next to it.]
NARRATOR: But really, gems are minerals or stones
[A cartoon crystal and a cartoon rock appear side-by-side. A saw comes down and transforms them into identical cut sparkling gems.]
NARRATOR: that have been cut, ground and polished by people to enhance their beauty.
[A split screen shows an uncut mineral next to a finished and polished gem.]
NARRATOR: A finished gem may look very different from the original mineral it was carved from!
[A bell-shaped blue gem appears, and the layers of flat faces outlining it are highlighted.]
NARRATOR: Many times, gems are shaped with different flat faces to catch and scatter light.
[An opal necklace appears.]
NARRATOR: They aren’t always minerals, either
[The screen fades to show images of a coral necklace, a pearl necklace, and a bright yellow gem.]
NARRATOR: – they can be made of things that come from animals and plants,
[Drawings of a coral and a mollusc with a pearl appear next to the coral and pearl necklaces, and a drawing of an ant in amber appears next to the yellow gem.]
NARRATOR: like pearls or amber,
[Two cartoon lasers point at a platform, and out of a cloud of cartoon smoke a sparkling white diamond-like gem emerges.]
NARRATOR: or they might even be manmade in a lab.
[Text appears: “Let’s make like a crystal and repeat that one more time.”]
NARRATOR: Let’s make like a crystal and repeat that one more time.
[A gold cubic crystal appears. Text appears: “Pyrite (fool’s gold)”]
NARRATOR: Think about pyrite, or fool’s gold.
[Another pyrite mineral appears in the background. Above the word “pyrite” two “S” circles appear (sulfur) and one “Fe” circle appears (iron).]
NARRATOR: Pyrite is a mineral made of iron and sulfur.
[The elements disappear and are replaced with a drawing of a cube.]
NARRATOR: Those elements come together in the shape of a cube,
[Text changes from “pyrite” to “pyrite crystal” as it reveals the pyramid-shaped hunk of pyrite behind the text.]
NARRATOR: and repeat to form a pyrite crystal.
[More pyrite crystals appear, these ones more cubic. Lines draw attention to the sharp edges and flat faces of the crystal.]
NARRATOR: These crystals can get so big you can see them with your naked eye.
[A gray rock appears with gold pyramids embedded in them, which are circled. Text appears: “Slate (rock)”]
NARRATOR: Other times, the pyrite crystals are just flecks in a rock like slate.
[Three black faceted and polished gems appear with cartoon sparkles next to them. Text appears: “pyrite gems.”]
NARRATOR: And if it was cut and polished with flat faces, it would be considered a pyrite gem.
[A pyramid-shaped turquoise-colored fluorite mineral appears.]
NARRATOR: So, there you have it, crystal clear:
[In order, the cartoon drawings and labels for minerals, gems, rocks, and crystals appear.]
NARRATOR: the difference between minerals, gems, rocks, and crystals.
How can you distinguish rock from a mineral? Is that a gem, or is it a crystal? Learn what all these words really mean in this video!
See more rocks, minerals, gems, and crystals in the Mignone Halls of Gems and Minerals. The galleries feature more than 5,000 specimens from 98 countries and tell the fascinating story of how the vast diversity of mineral species arose on our planet.