The List: 5 Interesting Rocks and Minerals Found in Easton

Did you know Easton is a favorite destination for rock hounds? More than 50 different kinds of rocks and minerals are found in Easton, particularly at the C.K. Williams Quarry. Some are quite common: others are more rare, and at least one is found only in Easton. Here are five interesting ones you may find if you look.

Quartz - It's nearly impossible not to find quartz and quartzite, as that comprises a good portion of the rock that Easton sits on. Tumbled stones, along with points and point clusters are quite common, and shades vary from white or clear to a reddish-yellow, reflecting the high iron content in the local area. Quartz exhibits the piezoelectric effect, which can be demonstrated by striking two pieces of quartz together in the dark—upon contact, the stones will produce electricity in the form of light when subjected to the mechanical stress. Quartz is found virtually everywhere in Easton—even in the city itself. Look in places where there is bare ground, particularly just after it rains in places where water runoff exposes the mostly white or translucent stones. Test them in the dark—if they 'spark', you have quartz.

Eastonite - Easton is the only site where Eastonite is found. This unique green serpentine was named for Easton, when it was discovered by A.N. Winchell in the 1925 at the C.K.Williams quarry on College Hill. Another serpentine that can be found there is williamsite, named for L. K. Williams who classified the stone in 1840. Some specimens of both have been reported to be of high enough quality to be cut into cabochons for jewelry.

Magnetite - You're not very likely to find this one in the quarry, and large specimens are uncommon in the immediate area, but particles of this magnetically-charged rock can be gathered in Easton. Try dragging a magnet across the silt near the Bushkill Creek or on the banks of the Delaware or Lehigh rivers, or even go fishing in the waterways with a magnet on a string. Small black particles of magnetite, where present, will stick to the magnet. Magnetite has a high iron content that has picked up a magnetic charge from the earth—larger specimens were once known as lodestones and in times of antiquity were sometimes used as compasses. Gathering magnetite makes a good science demonstration for small children, or can be made into ferrofluid to the delight of scientifically and artistically creative adult children, as this amazing video shows.

Pyrite - Another mineral that is the result of the high iron content of the local area, pyrite, also known as fool's gold, can be found in the Williams Quarry. Specimens have also been found sporadically in other locations around the area. Look for a distinctive goldish metallic hue. Pyrite, and the related marcasite, which can also be found at the quarry, were once used for adorning costume jewelry.

Thorite, Thorogummite, Uraninite and Zircons – We lumped these four together because of their radioactivity factor and also because they all have a close relationship to each other.

Clear zircons have been used as diamond substitutes for centuries, while colored ones have adorned costume jewelry. Natural zircons have a tendency to get dull when exposed to sunlight over time due to zircons frequently having radioactive elements in their matrix—specimens that do are unstable and are heat-treated to stabilize them if being used for jewelry.

Thorite contains the radioactive element thorium. Thorogummite is produced when thorite decays. Uraninite contains uranium, as its name would suggest. These three minerals are often found intermingled, as is the case in Easton.

Thorite, thorogummite and uraninite are all radioactive minerals and while they generally pose little threat where they naturally occur, collectors should take due care if they decide to collect these minerals: They should be handled as little as possible, and hands should be washed after any contact. They should be stored in a sealed container away from light. Radioactive minerals should never stored in places where food is prepared or consumed, or in places where you spend a great deal of time, such as sleeping quarters.

Just a few more of the rocks and minerals that can be found at the C. K. Williams quarry site and around Easton include: calcite, chrysotile (more commonly known as asbestos), fluorite, gypsum, graphite, hematite, malachite, talc, topaz, tourmaline, and vermiculite. For a more complete list, check here.

For more information about rocks and minerals that can be found in Pennsylvania, check out this downloadable book from the Pennsylvania Department of Conservation and Natural Resources.