Mole Conversion, Part Deux

The Hall of the Mole King
It is your third night in the Mole King's prison. Three days ago, you unintentionally stumbled and intruded upon his lair. It was but the moles' duty to put you through the tests.

On the first day, they taught you of their sacred number, 6.022*10²³. On the second day, they built upon your known knowledge of chemistry, telling you of the subtle yet absolute connection between the elements, the mole, and their weight.

Earlier today, His Blindliness the Mole King presented you with the ultimate challenge of their race, conversions between the number of atoms, to weight, and back. He handed to you two objects. The first, a faint green emerald, clear as crystal, smooth as silk; the second, a round blue sapphire, as rich and dark as the ocean. These two objects, as the Mole King told you, were called Grues and Bleggs, respectively.

Grues, the Mole King told you, are a pure substance. Even at the atomic level, they are Grues, and every single Grue atom weighed 27.2u. Bleggs were similar in that they were also a pure substance, yet each Blegg atom weighed 19.3u.
The Mole King challenged you to find, by sunset, the approximate number of Grue atoms that resided within the stone, and the weight of the Blegg. He told you a mere two pieces of information in addition to what you learned the last two nights: that the Grue weighed 21.3 grams, and that 4.05*10²³ Blegg atoms forms the dark sapphire in your hand. If, by sundown, you have not yet come up with the answer, the mole kingdom will devour you. Literally. But of course, you already know how to derive the answer, and silently smirk as the Mole King leaves.

You know that you must first convert to moles, and then the desired quantity. You decide to find the answer to the Grue first. As Grue atoms weigh 27.2u, that means a mole of Grue atoms weighs 27.2g. Through this, you discover that the chunk of Grue is (21.3/27.2)=0.78 mol. And, by multiplying that with the moles' holy number, you obtain the answer, 4.71*10²³ atoms.

By similar reasoning, you know that a mole of Blegg weighs 19.3g. By dividing the number of atoms with the moles' glorious constant, you are aware that you hold, in your hand, [(4.05*10²³)/(6.022*10²³)] = 0.673 moles. Again, by simply multiplying this by the weight of one mole of Blegg, you find that the Blegg stone weighs 13.0g.

As the Mole King returned, you confidently tell him the answer. A look of shock registers, surprised that you could beat the challenge. Yet as he promised, he released you, back to where you came. But you yourself know, that never will you forget the lesson of the moles.