From the glassworksservices data

Colour Variation Material
Conditions
Red Ruby Se + CdS not in PbO glass
Reduced + on reheating
Au
Copper antique ruby Cu2O
Reduced + on reheating
Red violet MnO2 + Se Oxidised
Wine red Nd2O3 + Se
Not oxidised

Blue Blue CuO & CoO
Blue (viloet tint) CoO
Sky blue CuO
Blue green Fe2O3 + CoO, Cu0 + Cr2O3, FeO

Green I'm not going to type the following 14 combination of
elemental oxides in for varying green colours at the moment
I suggest you contact www.glassworksservcies.co.uk

Digit wrote:

Thanks for you links guys .. but still I need more info.

like for making red, i need copper but some mention selenium ..

even for blue or green - what are the alternatives to cobalt ?

Thank you so much