FactorShares, the exchange traded fund provider more commonly known for its suite of long/short strategies, is working on three new mining-related ETFs, two of which may be the first in their categories.

According to a recent Securities and Exchange Commission filing, FactorShares is working on a diamond/gemstone miner, mining services and junior silver miners ETF under the new PureFunds line.

The PureFunds ISE Diamond/Gemstone ETF (NYSEArca: GEMS) will follow the performance of the larges and most liquid companies that produce, explore and sell gemstones. It will be the first ETF to specifically target the precious gem industry. GEMS has a 0.69% expense ratio.

As of July 24, 2012, the underlying index had 26 constituents and 23 were foreign companies. Top holdings include Petra Diamonds Limited, Harry Winston Diamond Corp. and Chow Tai Fook Jewellery Group, each with a 7.1% weighting.

On the commodities side, the ETF industry is also working to engineer the first physically-backed diamond ETF. [Diamond ETFs Would Allow Investment in Precious Gems]

The PureFunds ISE Mining Service ETF (NYSEArca: MSXX) will track the largest and most liquid companies that facilitate the operations of mining services industry, from those that manufacture, lease, sell and provide equipment to miners, along with those that engage in exploration and extraction. MSXX has a 0.69% expense ratio.

As of July 24, 2012, the underlying index held 31 stocks and 28 were foreign holdings. Top holdings include Mineral Resources LTD, China Coal Energy Company H Shares and Joy Global, each with a 7.0% weighting.

The PureFunds ISE Junior Silver (Small Cap Miners/Explorers) ETF (NYSEArca: SILJ) will try to reflect the performance of small-cap companies in the silver industry, including those engaged in mining, exploring or refining silver. SILJ has a 0.69% expense ratio.

As of July 24, 2012, there were 28 constituents in the underlying index, 23 of which were foreign companies. The top holdings include Endeavour Silver Corp., Fortuna Silver MInes Inc. and McEwen Mining Inc., each with a 13.6% weighting.

The new silver ETF would be the first to target small-cap silver miners. Investors can currently gain broad exposure through the Global X Silver Miners ETF (NYSEArca: SIL) and the iSharse MSCI Global Silver Miners Fund (NYSEArca: SLVP). [Gold Miner ETFs Outperforming Bullion in August]

For more information on new product launches, visit our new ETFs category.

Max Chen contributed to this article.