Quartz, variety chalcedony4. A white mineral, this is one of the most common minerals making up the earth’s crust. It comes in many forms including clear crystals, purple amethyst, a pink rose color, and as agate, jasper, fint, and petrified wood. The mineral is quartz and the various names are used for the way it looks or the color it is. This sample is quartz from the Superstition Mountains here in Pinal and Maricopa Counties, and this form is called chalcedony or desert rose.

Quartz has a chemical formula of SiO2 (one Silicon, two Oxygen atoms).

It can be a range of different colors from colorless through various colors to black

The mineral hardness scale runs from 0 to 10, and quartz has a hardness on the scale of 7.

If you rub a piece of quartz on a piece of white clay, you’d see that it leaves a white streak. DON’T do this without permission!

Quartz of various kinds has been used in jewelry for thousands of years, all over the world.

Most quartz crystalizes form from molten magma. The quartz is part of the magma and when it cools, the crystals form.




 Amethyst is a purple kind of quartz. The color comes when quartz is exposed to radiation, or when there is a small amount of iron mixed in with the quartz.

Rose Quartz

Rose Quartz is pink to red in color. Its color comes from a little titanium, iron, or manganese mixed in with the quartz. Rose quartz is the rock the earings are laying on.

Rocks that contain quartz include granite, sandstone, and shale. Other rocks that may contain quartz include schist, gneiss, and quartzite.