Dig Your Own Sapphire Gems In Montana

The first gem-quality sapphires in the United States were discovered in the gravels of the Missouri River in Lewis and Clark County, Montana in 1865. The discovery is attributed to Ed Collins, a gold miner who was working on one of the gravel benches, or "bars," just above the Missouri River near Helena. This find was followed by a number of other discoveries in the late 1800s, including Rock Creek in Granite County in 1892, and in Yogo Gulch in Judith Basin County in 1895. Facilities where the visitor can find his own sapphires are available in two areas, along the Missouri River and also at Rock Creek.  The adventure of finding your own sapphires is a fascinating and fun filled experience suitable for the entire family, including the kids.

While most of the sapphires produced from both Rock Creek and the Missouri River are of a pale color that is not particularly desirable for jewelry, gemologists have found that with special treatment to a red hot heat, the color of these gems is permanently altered to a much more desirable shade.  With the advent of successful heat-treating techniques for the Montana sapphires, this gem material has gained a much greater acceptance in the gemstone industry. This enhanced acceptance has resulted in a significant increase in the market for and value of U.S. sapphires.  Unfortunately, not all Montana sapphires are suitable for heat- treating because of variations in chemical composition within the crystal. Also, the sapphires from the Missouri River respond to heat-treating differently than those from Rock Creek The response to heat-treating can vary also depending upon the method (individual) used to treat the sapphires. Nearly all the sapphires in the world go through a heat treating process which improves the clarity of the stone and often intensifies the color. This change is within the entire stone, not just on the outer surface of the stone, as are some other enhancement processes used for other gemstones. For much more information about sapphire gems, be sure to check out my Sapphire information web page.

It has been found that a smaller percentage of the Missouri River sapphires respond positively to heat treatment as compared to those mined at Rock Creek. It is reported that 20% to 30% of Missouri River sapphires show a significant color improvement as a result of heat treatment. The corresponding treatment improvement rate for the equivalent Rock Creek material is in the range of 65%. Heat-treating produces desirable blue colors but also improves the color of fancy colored sapphires. Bright yellows and oranges can also be produced by heat-treating. Additionally, heat-treating improves the color of some pinks by removing colors that can interfere with the desirable pink shades. Heat treating and faceting services for your best gem stones are available to the public through the mines.  To learn more about facet cutting gemstones, be sure to see my Facet cutting information page

Heat Treated Sapphire Rough, Missouri River Area

Currently there are up to seven operations on the Missouri River that produce sapphires commercially and/or operate a dig-for-fee area. Not all of these may be active in any one year, so it is best to check around. Perhaps the best-known Sapphire mine on the Missouri River which is open to the public is the Spokane bar mine.  Digging your own sapphires is not free, but the costs are very reasonable. The Spokane gravel bar was named by geologists mapping the Missouri River area in the early 1900's. The name may have referred to the Spokane Hills which composed of Spokane shale. This gravel bar is the location of an exciting sapphire strike along the Missouri River.

The Missouri River has been dammed up to form Hauser Lake.  The lake is named after Samuel T. Hauser, one of Montana's Territorial Governors. Hauser played a significant role in Spokane Bar's mining history. Governor Hauser and his three partners worked the gravel bar for gold in the early days. Heavy stones plugged their sluice boxes, causing problems with gold recovery. The puzzled miners sent samples to England where these heavy pebbles were identified as sapphires. Unfortunately because of their less than desirable color, they were deemed valueless at the time (modern heat treatment methods were unknown at that time).

Visitors will find sapphires in every color at the Spokane Bar Sapphire Mine. The natural Sapphire crystal structure is hexagon with triangle terminations which are often flat. The most commonly found color at the mine is a green-blue shade. While blue sapphire is the best known color, usually heat treatment is required to produce this type of color in the Missouri River sapphires. Ruby is sapphire which is colored red, and it is one of the most prized gems of all.

The sapphires from the Missouri River gravels in Lewis and Clark County are a mixture of rough and pitted crystals showing well defined faces and completely rounded and smooth-surface highly stream worn pebbles. The majority of the material is pale blue or blue-green, with deep blue stones being quite rare. Stones also are found in pastel blue, green, pink, pale red, purple, yellow, and orange. Most of the stones recovered are less than 1/4" in diameter, but material between a quarter and a half inch in diameter is not uncommon. Material greater than half an inch in diameter is rare. The largest known sapphire from the Spokane Bar was 155 carats, found by a man from Idaho - unfortunately it was not of gem quality. The largest gem quality sapphire which has been found was 50 carats. Other gemstones which can be found at Spokane bar (although very uncommon), are diamond, topaz, citrine, and ruby. Garnets of several varieties can be found; the largest on record weighed 40 carats.

The Rock Creek sapphires are generally similar to the sapphires from the Missouri River but differ in the typical shape of the crystals. The stones are basically crude hexagonal plates about the same dimension in width and height, with a much higher percentage of the material being well rounded water worn pebbles. There appears to be more of the larger sized (greater than a half inch) material at rock Creek. Additionally, the natural colors of the Rock Creek material is just a bit better than the material from the Missouri River, and as a result a greater percentage of stones which are mined here can be heat-treated for a significant color improvement.

During the past several years, there has been only a single producer on Rock Creek. The gem mountain property has operated both a commercial recovery plant and a fee recovery area. The fee recovery area sold buckets of gravel for washing and also offered, for a predetermined fixed fee, the output of one day's operation of the commercial wash plant.

The presence of sapphire deposits at Rock Creek, Montana, has been known since the late 1890s. In fact, from 1906 to 1943 they were mined almost continuously to provide corundum for industrial applications. While most sapphires from this deposit are of gem clarity the hues in which they typically occur in rather uninteresting natural colors of pale blue pale green, faint pink, pale yellow, or near colorless. These colors are not commercially desirable. Although natural blue, yellow, and pink sapphires with good color saturation are found at Rock Creek, the quantities of natural material are just too small to justify commercial mining for these gems alone. Luckily, a large percentage of the pale, poorly colored gems can be improved by heat treatment.

Rock Creek is unique in that it was the only placer deposit in Montana rich enough to be mined for its sapphire alone. During the years from discovery to World War II, the main mining area was mined almost continuously. Enormous quantities of sapphire have been mined from Rock Creek over the years. Many tons of sapphire material was deemed sufficiently clean and fracture free to be used for precision industrial applications. Production of man made sapphire for watch bearings and other uses put an end to those operations. Sapphire has been found over a wide are and in many tributary creeks in the Rock Creek area.

Since 1943, there has been little interest in commercially mining the Rock Creek deposits. A portion of the deposit, currently known as the Gem Mountain Sapphire Mine, has been operated for many years as a fee digging area for hobbyists and individual gem miners. It is now operated as a fascinating tourist attraction where individuals can screen sapphires from sapphire-bearing ore mined by the operators.

At Gem Mountain, gravel dug by the mine owners is purchased and sorted for its sapphires. Every bucket is guaranteed to contain at least some sapphires. It is not necessary for the visitor to bring any equipment to the mine, as the facility provides everything a visitor needs to find their own Montana sapphires. Company staff teach how it is done, and do all the heavy lifting, so all the visitor has to do is show up and sift through the gravel to find the sapphires hidden in each bucket. From May 19th through October 9th, the Gem Mountain sapphire mine is open to the public seven days a week, from 9:00 am until 5:00 p.m. (from Memorial Day to Labor Day, evening hours are extended until 7 pm).

The process of recovering the sapphires from the gravel involves shaking a screen full of gravel under the water in the water troughs.  The material must be well washed in order to clarify what sapphires or other gems are present. The water rinses away the clay and mud that hide the sapphires from view. All sapphires are heavier than the general rocks in gravel so, as you shake the screen, the sapphires settle to the bottom. Once it is well washed and shaken, the screen is then quickly flipped over and dumped on a table. The sapphires that were on the bottom, are now on the top of the gravel, and you pick the gems out from among the gravels on your sorting table. Staff help new comers learn to screen the gravel and pick out the gems. Spotting the gems and collecting them is fun for everyone from the smallest child to the most serious rock hound.

Heat Treated and cut Montana Sapphires

Above: Gem Mountain Sapphire Mine Near Phillipsburg in Granite County, Montana

Above: Spokane Bar Sapphire Mine Near Helena in Lewis and Clark Co., Montana

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