Lighting fixtures and specialty chemicals may not be sexy, but that combination of business lines is serving Acuity Brands (NYSE:AYI) rather well these days. The diversified manufacturer reported quarterly earnings this morning, significantly besting analyst expectations.

Sales climbed 11% year over year to $603 million, and net GAAP earnings per diluted share landed at $0.63, an improvement of 46% against the year-ago period. The four analysts following the company had forecast $583 million in sales and $0.57 EPS on average.

Management says that the improvement rests on higher unit volume, higher average selling prices, and improved operational efficiency, despite higher costs in both energy and raw materials. That's rather impressive. This time, the main growth stemmed from lighting operations; next time, the chemicals may be pulling their weight.

When comparing Acuity to its competition, I found that the company is growing revenues about as fast as any of its peers, but net income is outpacing everybody from lamp makers Hubbell (NYSE:HUB-A) (NYSE:HUB-B) and Cooper Industries (NYSE:CBE) to chemicals competitors Ecolab (NYSE:ECL) and Procter & Gamble (NYSE:PG).

Here's the interesting part: All of these businesses are sporting much higher net margins than Acuity, which should leave plenty of room for future operational improvement. Acuity has indeed improved trailing-12-month net margins for the last six quarters.

Genlyte Group (NASDAQ:GLYT) is very similar to Acuity in size and growth rates, and more of a pure play on the lighting industry, if that's your thing. If you're interested in comparing the two, make sure to note that Genlyte is already operating very efficiently, and may run into slower earnings growth soon. But they both look like decent small-cap industrial businesses.

With a market cap just less than $2 billion, and only two main business lines, Acuity Brands won't be mistaken for Berkshire Hathaway anytime soon. But the smaller of these two well-diversified companies seems to have a good thing going nonetheless.

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Fool contributor Anders Bylund owns none of the stocks discussed here. Foolish disclosure is sparkling clean and well-lit.