Faceted domed acrylic crystal

A crystal cut to catch the light

The faceted domed crystal combines a slight dome with a surface divided into flat planes, the facets, which reflect light at different angles. This type of acrylic crystal, also called Plexiglas or hesalite, is often found on vintage watches, particularly ladies' watches and decorative models with small cases. It is generally suitable when the original crystal was already faceted: a smooth crystal would change the look of the watch.

Strengths and weaknesses of Plexiglas

Like any acrylic crystal, this one is lightweight and does not shatter into sharp fragments. Its hardness is low, so it scratches easily, especially on the edges between two facets. Polishing removes light marks, but here it takes a little more care to avoid rounding off the edges. For the method, refer to the guide to polishing an acrylic crystal.

Measuring, step by step

• Remove the old crystal.
• Measure it with a calliper, taking the diameter at the base of the crystal, on the edge that fits into the bezel.
• Choose a diameter slightly larger than the seat.

Why oversize? An acrylic crystal is generally compressed when fitted, then expands and is held by pressure in the bezel. The margin required varies between cases; the measuring guide gives you all the useful pointers.

Find your diameter

Just below, a table summarises the diameters available for this faceted crystal.

Available diameters