Convert from momme [Japan] to megatonne

Unit Definition (momme [Japan])
The momme [Japan] is a traditional Japanese weight unit corresponding to the Chinese mace. Jewelers continue to use the momme to measure the weight of cultured pearls; for this purpose it equals exactly 3.75 grams (about 0.132 ounce) or 18.75 carats. The unit is commonly pronounced "mommy" in English.

Unit Definition (megatonne)
The megatonne is a metric unit of mass or weight equal to one million metric tons (tonnes), one teragram (Tg), or about 2.2046 billion pounds.