Such dust belts typically contain a spectrum of rocks of different sizes, and the distribution of dust strongly suggests at least one Mars mass worth of rocks 10 meters (30 feet) wide or smaller and up to several Earth masses of material if larger rocks are present, which Lisse says is very plausible but more speculative. (scientificamerican.com)
Therefore, astronomers, their press officers and reporters are jumping the gun crying, «Earth» with every exoplanet discovery of a nearly Earth mass planet. (seeker.com)
(They also dialed back the gold - formation estimate to 3 - 13 Earth masses worth.) (businessinsider.com)