Is it quinarius?

Pictured coin has only 1,67 gr and the largest diameter of flan is 21,03 mm. Inner circle has 17-18 mm. Is it quinarius RIC IV-3 119? Denarius should be far much haevier. 

That's an interesting coin. The diameter is that of a typical denarius (range 19-21 mm), but the weight is a bit more than half that of an average denarius (range 2.18 to 3.7 grams). Given that a quinarius was valued at half a denarius, it should be half the weight of one. So I would lean towards labelling this a quinarius just based on weight, not diameter.

Thank you for your opinion. I found about 20 sales of Gordian III quinarii. There are two groups according to description made by auction houses. First larger goup are coins with diamater about 16 mm. The second group are coins with diameter 20 - 21 mm.  The problem is that I did not find second piece to the my pictured coin to compare… It is not easy how to describe this coin. But I think it is not a fake.