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Sand Collection

Sand Collection

My name is Kate, and I manage the Collectors' Corner at the Science Museum. I collect sands from all over the world.

I have about 400 samples and have been collecting sands for about 20 years with the help of friends and acquaintances. My fascination began when I played at the Lake Michigan beach as a child. When I began collecting, I never imagined sands could be so different from one beach to the next.

I find sands interesting because the grains tell stories about millions of years of geologic history. In addition, I am intrigued at the beauty and variety of colors and textures, plus the surprises visible under magnification.

Visit the Collectors' Corner to see many varieties. Bring us a film can of dry sand from your next vacation to add to our collection!

Magnified Sands

Cape Canaveral, Florida
Cape Canaveral, Florida
Many of the grains of sand found in Florida are shell fragments.

The green grains are olivine. The black grains are fragments of basaltic lava, the clear grains are quartz.

Abbott's Lagoon, Point Reyes, California
Abbott's Laggon, Point Reyes, California
California Sand grains include many volcanic rock fragments.

Big Sur, California
Big Sur, California
The pink grains are garnet, the clear are quartz, and the black are magnetite.

Sand is a ground-up history of part of the earth's crust.

Where does sand come from?
Sand on the sea and lake shores comes from the weathering of rocks along the coastal regions and from continental mountains. The actions of freezing or thawing, blowing and bumping along by the wind and waves, or rolling or bouncing down a river reduces boulders to pebbles to sand grains.

Coarse or fine grains?
The sand grain size depends on the nature of the sea currents and waves. Small, light particles are carried far. Large, heavier particles sink more readily. Sorting of sand grains is forever going on. Some beaches have sand grains of all different sizes, others are well sorted with grains all of the same size. With every storm or tide, the materials is sifted or sorted so that beaches are continually being remade.

All the same or different colored sand grains?
One beach may contain all of one kind of sand grains. Another beach may contain sand grains of many kinds of rocks. The kinds of sand grains depends on the origin of the mother rock and the waves and currents. Other beaches may contains shells and coral fragments as "sand" grains.

Angular or round sand grains?
Sand grains can vary in shape. Well rounded grains have rolled around for longer than angular grains. "New" sand from recent volcanic eruptions or recently eroded rocks may be more angular.

Clear, black, green, or pink grains?
The most common rock or mineral in sand is quartz. It is insoluble in water, hard, and does not break down or decompose. Dark sands may contain hornblende, basalt, magnetite, or manganese. Coral and Shell parts in sand can be pink, white, striped, or notched.

Is sand important?
Sand is important in the manufacturing and oil businesses. Pure sand is used in glass making, sandblasting, and the sandpaper industries. Other sand is used to make pottery, for making casts for metal parts, and for making concrete.

I- 35W-Bridge Minneapolis, Minnesota

This plain brown sand, dredged at the site of the I-35W bridge collapse 8/1/2007, includes sediments the Mississippi River hauls downstream from its headwaters in Northern Minnesota.

The sand grains originated as both intrusive and extrusive igneous rocks and other ancient rocks that the Ice Age glaciers ground up and transported. Grains derived from granite include clear quartz and pink feldspar; grains from the northern part of the state include magnetite, ilmenite, red agates and other lithics. The sample also includes evidence of the industrial city: chunks of bubbly slag, charcoal, and a piece of yellow road-strip paint embedded with some reflective glass beads. The hollowed orb is likely from a sand blasting operation. The semi-circle bottom left is part of a freshwater mollusk.

Mar Del Plata, Argentina

Argentina's premier beach resort, dating back to the late 1880s, Mar del Plata is located on the Atlantic Ocean 250 miles southeast of Buenos Aires.

In addition to miles of "golden" sands, the shoreline boasts one of the oldest rock formations on the planet. The Tandilia System stretches across the province and enters the ocean near Mar del Plata. This two billion year old formation includes igneous and metamorphic rocks once part of the supercontinent Rodinia that predates Pangaea.

Mineral grains include clear quartz and reddish feldspar. Also abundant are highly polished white and tan mollusc shell fragments including the multi-layered brown chunk (lower center). Thin, translucent chips may come from intertidal coquina bivalves like Donax. The blue-black grain may be from a Mytilus mussel.

Tumon Bay, Guam

On Guam, the largest of the Mariana Islands, Tumon Bay is a tourist epicenter. A fringing reef extends 100 meters offshore and protects the vast bay. On the reef's ocean edge, the intertidal flat rises to form a crest that is exposed during low tides and scoured by ocean waves during high tide.

The stars in this sand are foraminifera (forams for short). These single-celled amoeba relatives secrete a calcium carbonate "shell" or test. Pores in the test allow cell extensions to extend out for capturing food particles. Other grains include bits of skeletal material from additional reef builders: coralline algae (the rod-shaped fragments and chalky flattened discs and lumps) and coral skeletons (the more angular and glassy-looking bits).

Jeffreys Bay, South Africa, East Cape (Indian Ocean)

Jeffreys Bay, on the Eastern Cape of Africa, is famous for its surfing and pristine beaches. The landscape of the area is dominated by two mountain ranges with high peaks and rocks that date back 800 million years to the Pre-Cambrian. Quartz-rich sandstones in colors from pink to clear and brownish dominate the landscape. Transported over millennia down the mountain streams, quartz makes up the bulk of the grains in this sample.

Colorful biogenic contributions from the ocean include shells and skeletal shards from invertebrates and algae, including: a red nerite snail; numerous bivalve fragments; green, purple and bi-color urchin spines; yellowish rods of coralline algae and numerous ribbed shell fragments. The white disk with a hole (left of the red nerite) is likely a foram. 126

Valentino Beach, Mazatlan, Mexico

A tourist destination on Mexico's Pacific coast, Mazatlan is located at the mouth of the Gulf of California. Characterized by high biodiversity, this region supports diverse coastal ecosystems and thousands of marine species.

Ranging from translucent white to orange and brown, the glassy sand grains are primarily from calcium carbonate mollusc shells, including the tooth-shaped fragment at 4 o'clock. A narrow cone-shaped snail at about 7 o'clock is an example of a micromollusc—a mollusc species that doesn't grow any larger than a grain of rice.

The rugged Sierra Madre Occidental mountains along this coastline are comprised of rocks that chronicle volcanism and pyroclastic activity. The cement-like grains, called ignimbrites, are cemented pumice and ash. The black grain is probably basalt.

Bretignolles sur Mer, France

Bretignolles sur Mer is on the Atlantic coast of France. This concentration of pink and red garnets, black iron-rich minerals (mostly magnetite), green epidote, and milky to clear quartz makes this a placer deposit. Placer mineral deposits show up on beaches where the waves, wind and tides segregate the heavy minerals from the less dense ones and form colorful lines and dark swaths on the less dense grains, often quartz and feldspar.

The geology of this region is complex and dates to about 280 million years ago with the collision of two continents, mountain building, and the formation of the supercontinent of Pangaea. The mineral grains in this sand are derived from the roots of those ancient mountains.

Knife River, Minnesota Lake Superior

With the help of the glaciers, this rocky looking sand eroded from the iron-rich volcanic tocks common in northern Minnesota. Near the Lake Superior shoreline, the rivers have cut deep gorges and carry sediments from the uplands to the lake.

Many of these grains have a red hue—a clue they contain some iron. Magnetite, an iron mineral is the black grain in this sand sample. The lake Superior region has a rich mineral history. Beginning in the later 1800s, miners extracted massive amounts of copper from Michigan and iron from Minnesota, Wisconsin and Michigan. Some mining continues today.