That is normal and is part of labradorite’s optical effect. Labradorescence is strongly dependent on the angle of the stone, light and viewer, so the colour flash may appear, disappear or change as the piece is moved.

No. Labradorescence is a natural optical effect produced by light interacting with fine internal layers within the feldspar. The blue, green, gold and other flashes are therefore part of the stone rather than a surface colour added afterwards.

Position the stones where customers can easily see and gently turn them under the light. A display that allows the viewing angle to change will show the flash much better than placing every piece flat and expecting it to look equally colourful from one fixed direction.

Labradorite belongs to the feldspar family, which is around 6 on the Mohs hardness scale and has natural cleavage planes. It can therefore chip or fracture from a hard knock, so larger pieces should sit securely and smaller stones are better kept from constantly knocking together.

For ordinary shop dust and fingerprints, use a soft cloth; mild soapy water can be used when necessary, followed by careful drying. Steam and ultrasonic cleaners are best avoided with feldspar because of its cleavage and relative brittleness.

It is worth checking before they go on display. The statement pieces are substantial solid stones, so use strong, level shelving and keep them safely back from the edge, particularly where customers are encouraged to handle the stock.