Getting investors into the shale revolution in the US energy sector has been a difficult task at a time when natural gas prices themselves are low and individual firms are shifting their focus.

Firms involved in the sector are often hard to value as the revolution (and its price impacts) wreak havoc on their plans by opening up new possibilities and shifting profit scenarios.

A firm specializing in exchange traded funds, which seek to replicate in a single product the performance of an index of shares of similar companies, has now launched a fund it calls the Market Vectors Unconventional Oil & Gas ETF. Van Eck’s new fund is “designed to provide investors with pure play exposure to this fast-growing segment of the energy sector,” and includes shares in companies accessing coal bed methane, coal seam gas, shale oil, tight natural gas and tight sands.

The scale of shale oil and gas plays has been referred to as “game changing” so often the term has become rote for shareholders in large energy firms increasingly taking roles in partnerships and investing in new infrastructure that leverage exposure to shale gas and liquids. Watch a video of the America’s Natural Gas Association chief economist Sara Banaszak discussing the transforming scale of the resource here.

In launching its new ETF, which trades under the New York Stock Exchange symbol “FRAK,” Van Eck uses the familiar ‘game changing’ line but also notes unconventional technologies are okaying as much of a role as the scale of resources.

“Technological advancements and cost efficiencies have attracted interest from major global energy companies that are eager to participate, as evidenced by rising M&A activity,” Van Eck said.

The index that FRAK will replicate includes companies that “derive the majority of their revenues from unconventional oil and gas (or have properties with the potential to do so), have a market cap in excess of $150 million, a three-month average daily trading volume of at least $1 million, and a minimum trading volume of 250,000 shares each month over the preceding six months. As of the end of January 2012, 43 companies qualified for inclusion.

Many Americans already own shares of oil and natural gas firms through their retirement accounts, many of which hold shares in the largest public companies.

Photo Caption: A trader monitors stock activity on the floor of the New York Stock Exchange on February 8, 2012 in New York City. The Dow Jones industrial average gained 5.75 points to close at 12,883.95, the highest close since May 19, 2008, the last time it finished above 13,000.