Kyanite crystal sheaths from Minas Gerais, Brazil, which show excellent accicular crystal form. Kyanite is often found in hues of blue, this black variation is rare and unusual, making such specimens highly sought after. Kyanite is a silicate mineral which is often found in pegmatites or in sedimentary rocks. However, it also occurs in metamorphic rocks, where its presence is often an indication of high pressure. The name comes from the Greek word, kyanos, which means 'dark blue' a reference to the rich blue colour that it is usually found in. Even more interesting is that these mineral specimens from Madagascar appear to all show excellent radiating sheath forms, while most kyanite does, the tight, clean nature of these crystals is far higher in quality. The samples are approximately 3 inches in length with the width varying but all are quite thin, they come supplied in a plastic box with an information label.