Flame Test #3

This flame test is of an inorganic compound produced by reacting a Group 1 metal with nitric acid.

It is a deliquescent compound in that it can absorb large amounts of water from the atmosphere.

The compound is used in the manufacture of fireworks and flares.

The name of the metal in the compound derives from the Greek word for stone.

There - I've given you far too much to go on.

What could it be?

Flame tests make my day!