Some jewelers say online companies should have to collect sales tax just like they do. But that will take legislation—which may not be a sure thingIf you ask retailers like John Henne, they say the Internet sales tax issue is all about fairness.“We’re not afraid to compete with the Internet,” says the president of Henne Jewelers in Pittsburgh. “But we can’t give customers a 7 percent price advantage.”Currently, if a customer goes into his store and buys a diamond, he pays 6 percent Pennsylvania sales tax. Yet if a customer stands outside his store and buys a diamond on his phone from an e-tailer, the customer doesn’t pay any. And with an expensive purchase, that can spell the difference between someone who buys and someone who walks. “We see it most often with engagement rings—when things start to get over $10,000 and that means about $1,000 tax,” Henne says. “Whe