This page gathers the stones in our collection whose geographic origin is Madagascar, an island whose varied geology yields an unusually broad spectrum of gem species. Here you will find sphene, rainbow moonstone, aquamarine, blue sapphire and blue star sapphire — a grouping that spans three very different optical characters rather than a single look.
Sphene (titanite) is prized for dispersion that exceeds diamond, throwing flashes of spectral colour when cut with precision. Aquamarine, a beryl coloured by iron, is valued for clarity and a calm sea-blue to greenish-blue tone. Blue sapphire is corundum coloured by traces of iron and titanium, offering the hardness and saturation expected of the species, while blue star sapphire carries oriented rutile inclusions that produce a six-rayed asterism under a single light source and is therefore cut en cabochon. Rainbow moonstone, a feldspar, displays adularescence — a blue schiller drifting across the surface as the stone moves.
Choosing between them is less a question of rarity than of behaviour: consider whether you want fire, transparent colour, asterism or a moving sheen, and how durable the stone must be for its intended setting.
