Safe Havens? As the price of diamonds has appreciated, the market is again seeing attempts to promote the gems as an investment. A Rye Brook, N.Y., investment firm, IndexIQ Advisors, filed paperwork with the Securities and Exchange Commission for permission to list what is believed to be the first U.S.-based exchange-traded fund to invest in diamonds. The IQ Physical Diamond Trust would hold natural 1 ct. diamonds certified by the Gemological Institute of America, says the SEC filing. “The diamond market has been less prone to the cyclical price fluctuations typical of many commodities due both to its retail product nature and the strong market position of major market participants,” the filing says. A rep for IndexIQ Advisors declined comment, citing the SEC-mandated quiet period before going public. Last August, Pinnacle Diamonds, a company in Sherman Oaks, Calif., began