Sci-Fi Technocrats (cyborgs) vs People with mental powers

Question

Earth is at the brink of an ecological catastrophe, polluted, ravaged by wars, and was abandoned by the majority of its population who left in space ships.

For generations their society relied on technologies and they developed a military style technocracy merging with the machines becoming almost cyborgs. They build their ships from an extremely durable material "diamantee" or something along those lines.

In the meanwhile a small amount of people remained on Earth. They renounced their dependence on technologies and instead cherished the abilities within themselves such as Telepathy, Telekinesis, etc - Earth managed to heal and they lived in total harmony with nature living miles apart.

At one point the departed people (technocrats) return on their ships and try to reconquer the Earth - the people with mental powers who were left resist....

Read about 2006

If anyone knows anything about the title or the author I would very much appreciate the info - I have been looking for this book about 15 years

Answer 1

This looks to be Adiamante be L.E. Modesitt Jr.

The story centres around the return to earth / attempted annexation of earth by cyborged descendants of colonists.

The powers of the those remaining on earth are tech mediated rather than magical but not visible/showy.

Those who remained on earth had gone for a low impact on the environment world, low population with tech used only where needed and very much behind the scenes which led the cyborgs to underestimate their military abilities.

There is (as far as I can remember) a history of a fall from a much higher tech level (millennia previously?) and the new cyborg ships made of Adiamante (super material) are the only ones they have been able to make - just got back to that level of tech. There are comments about fragments of the stuff lying around the Earth