These look like very typical Chinese stones. What I like to call "jelly-carnelian." They have a nice orange color, and a translucency that is fatty and looks good enough to eat. As I remarked, I don't know whether Chinese stoneworkers heat-treated or other manipulated agate to enhance its color. The least one can say is that it is very possible or even likely.

However, with exceptions, the result of these treatments does not yield a visual appearance that can be spotted or distinguished from "natural carnelian." These processes mimic or accelerate what happens in nature—so we should not expect to see a difference. It is especially difficult to say much from a photograph on a screen, because (we all know) the color may be manipulated or may appear unexpecetedly different on my screen, versus any other screen. But what I see (or think I see) in your image is conventional and expected.

The exceptions I have seen recently are the new carnelian beads being produced in China. These began to be sold in 1997 (the year I went to Taipei and Beijing), and I believe I was the first American to bring them back to the US. The red treatment is quite distinctive, in-part because of the quality of the agate material used, and partly because of their version of the coloring process—it yielding a rather unnatural and unexpected red color, that is quite different from the carnelians found/used/made at other industries, such as India, old China, South America, etc.

Jamey