Convert from picogram to obolus [Ancient Rome]

Unit Definition (picogram)
The picogram is a metric unit of mass equal to 10E-12 gram or one millionth of a microgram.

Unit Definition (obolus [Ancient Rome])
The obolus [Ancient Rome] is a historic unit of weight or mass. The obol is a very small weight that originated as the weight of a tiny Greek coin. In Rome, the obolus was equal to 1/48 Roman ounce (uncia) or about 0.57 gram.