Native PowerPoint offers gold, silver, brass as gradient pre-sets.
Click on an autoshape to select it, then click on Format, Autoshape.
On the color tab, click the drop down arrow and select fill effects.
On the gradient tab, click preset and click the preset colors drop down arrow.
Gold, Silver and Brass are near the bottom.
You can use gradient colors for autoshapes and backgrounds.
You can also get to the color settings through the color icon (paint bucket)
in the bottom toolbar.
Having said all that, Troy's recommendation will probably enable you to
create a much nicer effect, but if PPT is all you have, the above should work
ok.