Top row, from left to right: a square-cut dark blue aquamarine gemstone; an oval-cut dark blue topaz gemstone; an octahedral cleavage specimen of blue fluorite; an oval cushion-cut light blue aquamarine gemstone.
Second row: a prismatic crystal of blue topaz; a hexagonal crystal of blue aquamarine; an oval-cut blue tourmaline (indicolite) gemstone.
Third row: an oval-cut blue sapphire gemstone; an oval-cut blue sapphire gemstone; a prismatic crystal of blue tourmaline (indicolite).
Bottom row: a square-cut dark blue spinel; a natural blue sapphire crystal with strong color zoning; an oval-cut dark blue zircon gemstone; a rectangular step-cut dark blue tourmaline (indicolite) gemstone.