You create a texture in Corel texture, (or similar) and you really work at the pixel depths and color layers until you get the right green - yellow - red mix for a gold, (gold is white yellow in the hilite, then a little red, lotta yellow, coming out of it to the darker end, then dab of red, loads of yellow, big dab of green, then green yellow black in to the shadow.)
If you have a texture program or plugin that allows surface texture algoritms to be applied, work with these layered filters for the feel of the metal, you then use lighting effects to add lustre. This is really labor intensive, maddening stuff, but you end up with a gold you'd swear was cast out of metal, and a brass, and a silver, if you wish.
You then save the resulting texture files as bit maps and use them as a bitmap fill in Photopaint, stretched across a rectangle (don't use original size).
This gives you a rectangle with a beautiful metallic effect.
You then open a linear radial fill and eyedrop color edit it so the lightest of the gold is in the centre of the edit bar and gradually transitioning through many shades to the darkest at each end(or whatever disposition of highlights and shadows you need).
Next save it as a preset. Save yr texture file and all the other files you've made, 'cos something will always clobber a graphics effect that takes the most work to achieve ..."Well, you shoulda told me you had files in the textures directory you made yourself..." Y'know?