Crystal Park is a unique recreation area at an elevation of 7,800 feet in the Pioneer Mountains in southwest Montana. The Butte Mineral and Gem Club maintains mining claims at Crystal Park open to the public for digging quartz crystals. The Forest Service and Butte Mineral and Gem Club work together to promote, develop and maintain this site for recreation. Crystal Park is open May 15 - September 30. There is no charge, although donations for support of operations and maintenance of the site are appreciated.
Crystal Park Geology:
Like most of the eastern Pioneer Mountains the "country rock" or bedrock at Crystal Park is granite. About 68 million years ago, the Pioneer Batholith intruded the area, pushing up molten granite to form the Pioneer Mountain range. The granite was about 3,000 degrees C or approximately 6,000 degrees F. As the granite cooled, super-heated water circulated through it, carrying quartz, pyrite, and other minerals in solution. As the granite and the water continued to cool, the minerals precipitated out and were deposited as crystals in veins and cavities (called "vugs"). The molten granite continued to cool and solidify for several thousand years.
Later, glaciers, surface and ground water, weathering and other erosional processes exposed the minerals and crystals to air and groundwater. The original crystals remained unchanged, but when the rock temperature was 300 to 500 degrees C, and iron (from pyrite) was available, amethyst quartz crystals were formed. Amethyst crystals sometimes formed directly on another colorless crystal.
Quartz crystals at Crystal Park seem randomly distributed because weathering of the granite has freed them from veins where they formed. Careful digging can sometimes expose traces of veins seen as reddish-brown zones in the light-colored granite. By tracing remnant veins, "pockets" of crystals are sometimes found.
Crystal Park Facilities :
About 30 acres of the nearly 200 acres set aside for crystal digging are currently open. Digging areas are a short walk from paved parking. Facilities include: a hand pump water well, three picnic sites with tables and grills, information signs, toilets, and a paved trail with benches and an overlook. The facilities are designed to be universally accessible. Crystal Park is open for day use. There are Forest Service campgrounds along the Scenic Byway to the north and south of Crystal Park. A host is usually present at Crystal Park to assist visitors, maintain the facilities, and to ensure the rules are followed.
About Quartz Crystals:
Quartz crystals have six sides. A normal quartz crystal is a six-sided (hexagonal) prism, terminating at both ends in two sets of rhombohedral faces, each set with three faces. Each alternate face belongs to one rhombohedral set, and in most crystals one set is larger and more developed than the other. The six faces are termed "pyramid" faces. Other small faces may be present near the junction of the prism and the rhombohedral faces.
Quartz crystals may be clear or cloudy, white, gray or purple. Within clear crystals, inclusions of water or other minerals are often seen. White "milky" crystals are the result of finely disseminated gas bubbles. Gray, purple and other colors are caused by minerals in the quartz. Gray crystals are known as "smoky" and purple crystals are called "amethyst".
Quartz crystals at Crystal Park can be smaller than your thumb or several inches long. They may be single, in pairs or clusters. Sometimes a larger crystal will be found on the end of a smaller one, forming what is called a "scepter".
For digging, a shovel, hand trowel, gardener's hand cultivator, and gloves are useful. Some people like to use a screen with 1/4" mesh to sift the sandy soil for crystals. You will have to carry your tools to the digging area from the parking lot, so a pack will come in handy. Explosives and mechanical equipment are strictly prohibited.
Decomposed granite is like coarse sand, so digging crystals at Crystal Park is not difficult; but you must be careful! This sandy material will cave in easily, quickly burying and suffocating anyone trapped under it. Be sure to follow the rules for safe digging. Do not dig tunnels, deep steep-walled pits, or leave overhanging banks.
Experienced diggers examine all the dirt they move. A screen is very helpful for this. You can damage crystals by striking them with a shovel or pick, so dig slowly and carefully.
Even in the hottest part of the summer, be prepared for cool weather at Crystal Park; a rain or snow shower can happen any day of the year at this high elevation. Sturdy shoes, a hat, sunscreen and a jacket will help you enjoy the setting; be sure to bring insect repellent too.
Handle your crystals carefully to preserve their sharp points and special features. You may wash colorless quartz crystals in a warm bleach solution to clean and brighten them. Amethyst crystals are heat-sensitive; they may shatter in hot water or lose their purple color at high temperatures.
Some crystals found at Crystal Park are suitable for jewelry, either in natural form or faceted. Some collectors prize quartz crystals of particularly high quality and unusual form. Most people simply enjoy their crystals as a memento of their visit.
How To Get There:
- From Butte:
Drive 3.5 miles west on I-90 to the I-15 South exit. Drive 17 miles south on I-15 to the Divide exit. From Divide, travel 11 miles west on Highway 43 to the town of Wise River. Just past Wise River, turn south on the Pioneer Mountains Scenic Byway and drive about 25 miles to Crystal Park. The road is paved all the way.
- From Dillon: Drive 2.5 miles south from Dillon on I-25 to the Highway 278 exit; then 22 miles west on Highway 278 to the Pioneer Mountains Scenic Byway. Turn north at this intersection onto the Byway and drive about 17 miles up the Grasshopper Creek Valley to Crystal Park. The Byway is gravel from Highway 278 to about a mile south of Crystal Park.