# Yellow-amber debris above water filter: What is it?

I have some weird, yellow-amberish pebbles that have been filtered by my Zero waterfilter. Any idea what they are? Copper maybe?

The black stuff is charcoal from the filter.

The quality of the water in my area is fairly good, with a TDS of 40-60. With the filter, I have a TDS of 0, which is excellent. But I'm still curious as to what those things are.

• I would hazard a guess that they are spheres of silica, and are part of the filter that has come loose along with the charcoal. – Richard Terrett Oct 22 '13 at 4:46

It looks like ion exchange resin, it is used to specifically capture ions from water and replace them by others (either $\ce{H^+}$ or alkali metal ions.