This cannabis stock just made history

Is this the industry's watershed moment, or is this just a one-off exception?

The marijuana industry still isn't legal in the U.S. even though dozens of states permit marijuana for either recreational or medical use. There are even many marijuana companies that trade on the stock exchanges that you can invest in today to gain exposure to the fast-growing industry.

However, not all marijuana companies can trade on the NYSE or Nasdaq. Specifically, plant-touching marijuana companies based in the U.S. aren't able to do so because they operate in violation of federal laws. But in May, one stock became an exception to the rule and made history.