have i made melamine?

I am trying to make melamine from urea.

When heated, urea converts to ammonia and cyanic acid.

(NH2)2CO → HCNO + NH3

The cyanic acid then polymerizes to cyanuric acid which reacts with the ammonia to form melamine. This releases water, which reacts with cyanic acid forming carbon dioxide and ammonia.

6 HCNO + 3 NH3 → C3H6N6 + 3 CO2 + 3NH3

I started with 23g of urea. I heated the urea in a metal pot. It melted then started to release lots of smoke. The smoke smelled strongly of ammonia. After a while the mixture stopped smoking and solidified. I took it off the heat. I scraped the solid into a beaker and added 300ml of water. The solid did not dissolve.

Is there any easy way to test this substance to see if it is indeed melamine?

My guess is it's a mixture of melamine, melam and cyanuric acid. If this is so, how could I separate the melamine from these other products? Maybe sublimation?

Any help would be appreciated