Chapter B, Problem 61ES

Tanzanite. Tanzanite is a gemstone discovered in 1967 in the East African state of Tanzania, the only place in the world where it has been found. Rarer than diamond, tanzanite ranges in color from ultramarine blue to light violet-blue. The world’s biggest piece of tanzanite was unearthed near Tanzania’s Mount Kilimanjaro. The gemstone weighed 16,839 carats and was the size of a brick. A carat (also spelled karat) is a unit of weight for precious stones;

$1\text{ carat}=200\text{ mg}$.

Source: International Colored Gemstone Association; “World’s Biggest Tanzanite Gem Found Near Kilimanjaro,” Bloomberg.com, Aug. 3, 2005

How many grams is this record tanzanite gemstone?

Given that $1\text{ lb}=453.6\text{ g}$, how many ounces does this gemstone weigh?