Endogenous growth theories have paid insufficient attention to pattern
s of growth within subgroups of developing countries. Partly drawing o
n these theories, a mixed endogenous growth-technology diffusion model
is formulated with regard to developing mineral economies, The model
envisages an S-shaped double convergence long-term equilibrium, with t
he flex point possibly lying above the corresponding point for non-min
eral economies, The performance of a mineral economy is assumed to dep
end, among other factors, on the growth and instability of its main mi
neral commodity export price. The model is tested on cross-country dat
a.