A perfect Japan law twin from Mahaiza. Madagascar has a few localities that produce quartz twins (think of the amethyst or milky samples from Andilamena) but such samples are exceedingly rare from Mahaiza, despite the area producing industrial quartz by the ton.
Actually, this piece is exceptionally sharp and transparent for any Malagasy locality. It was purchased from an area dealer who handles large quantities of industrial quartz—from the vast quantities he handles, he obviously saw this one was special and set it aside.