This is a micro-cabinet, collector's piece, mineral specimen, Yogo sapphire in lamproite matrix. It is sitting on a display agate attached with specimen clay. The dark blue sapphire crystal measurement is 3.5 mm x 2.75 mm. This is a small chunky crystal instead of a plate. Rare piece. Would be excellent for a micro collection. Very rare specimen and very hard to come by anymore. From Judith Basin, Montana. Entire specimen measurement is 10 mm x 7.5 mm x 9 mm. YOGO SAPPHIRE IN THE MATRIX