Rogers Group, Inc. | Crushed Stone | Sand & Gravel | Asphalt Paving | Road Construction > Industry Resources > Rockology 101: Activities

1 cup white flour

½ cup salt

2 tsp alum

½ cup water

5 drops red food coloring

5 drops blue food coloring

3 drops yellow food coloring

1 cup coarse sand

½ cup gravel (2 colors – could use aquarium gravel)

1/8 cup oyster shells (really anything else could be added)

Please have an adult's supervision for this activity.

Students should make Homemade Stones about 1 week in advance of this lesson.

Mix the flour, sale and alum together in a large zip bag.

Add the water and food coloring. Knead the mixture until it is uniform in color and texture and no longer sticks to the sides of the bag. If needed, add more water if the dough is too crumbly.

Add the sand and the gravel mixture. Knead.

Divide the mixture into 18 ping pong size balls. Place the stone ball in your hand and with your thumb make a depression, sprinkle in oyster shells, then mold the dough around them.

Flatten the stone. Put them on the plate to dry. Turn every day until dry. Do not microwave or oven bake the stones -- they will get too hard.

If they get too hard, sprinkle them with water and let them sit awhile before using them.