Flux-Grown Synthetic Red Spinel: Why Basic Tests Can Be Misleading
A synthetic spinel is grown by people but has the identity of spinel. It is different from a material that only imitates spinel’s appearance. Flux-grown red spinel is a useful example of why a correct mineral identification does not always establish natural origin. Why routine measurements may overlap SSEF’s 2009 study reported flux-grown red spinels with refractive index and density similar to natural spinel. Their attractive appearance and fluorescence were also insufficient for reliable separation. A familiar result on a basic gem test therefore did not settle the formation question. What the researchers examined Microscopy revealed cavities containing flux residues, sometimes with gas bubbles, and a metallic flake in one specimen. Chemical and spectroscopic observations helped support the interpretation. Brown material inside a fissure must not automatically be labelled flux. Natural spinel can contain other brownish substances, and a similar-looking feature may have a diffe...