My investing idea for this week is fairly far off the radar. It’s an emerging markets company called Chemical and Mining Company of Chile (Sociedad Quimica Y Minra) (SQM). This medium-sized chemical and fertilizer company (last year’s sales were $1.68 billion) produces potassium nitrate, iodine, and lithium carbonate and distributes them around the world.

The company is thriving because it has a rich source for its minerals. But even more important, it has worked to create value-added products from what it mines, avoiding the extreme fluctuations that the commodity markets are prone to. Its other products include specialty plant nutrition products and the lithium that helps to power batteries and is useful in the ceramic and enamel industries.

In Q4 2007, the company achieved a robust 55% gain in earnings on a 15% bump in revenues. Since then, quarterly earnings growth has been 56%, 153% and 350%, leading to an after-tax profit margin of 32.2% in the latest quarter. There’s nothing commodity-like in those results.

SQM had a great year in 2005 and then it slowed down somewhat in 2006 and 2007. In 2008, the stock took off on a run that blasted it from 13 to 59 in just five months. The Big Bear of 2008 then mauled the stock, pushing it right back below 15 in less than four months.

The stock is now recovering, and has already topped 25. With a P/E ratio of 16, it’s not cheap, but it has the potential to react well to any good economic news.