Selenite or Satin Spar, which one do I have?

Selenite is one of our most popular items, be is in towers, lamps, polished forms like hearts or rough wands.  We even have a knife or 2 made from “selenite”.  But are these magical, fibrous things really selenite or are they Satin Spar? 

Let us start at the beginning of this saga.  Selenite and Satin Spar are forms of gypsum.  Gypsum is a soft sulphate mineral (with some calcium and water molecules thrown in) with many uses.  It is used as a fertiliser, in dry wall, blackboard chalk and is a main part of plater.  In fact, the name is derived from the Greek word gypsos meaning plaster.

Gypsum crystalises in different forms in nature.  There is the flattened, transparent, cleavable (capable of being split) masses called Selenite.  It can also occur in silky, fibrous form which is called Satin Spar.  Another form that gypsum occurs in is granular or quite compact. In hand-sized samples, it can be anywhere from transparent to opaque. A very fine-grained white or lightly tinted variety of gypsum is called Alabaster.  Alabaster has been used for centuries for carving and decorative work.  Let us also not forget those magical things called Desert Roses which normally forms in arid regions where gypsum occurs like flowers with grains of sand embedded inside the crystals.

Selenite is the name most people recognise, but Selenite crystals are in fact much rarer than Satin Spar. Selenite forms in large flat, transparent crystals sometimes called windows and can flake apart (cleavable as mentioned before).

Satin Spar is a name not as well-known as Selenite but it is the crystal type that most people are familiar with.  If you look online, most selenite offered for sale is Satin Spar. To prevent confusion most retailers (Forever Gems included) continue to call what is Satin Spar by the name most people know it as, Selenite.  Satin Spar crystals are fibrous and white and is available in towers rough wands or polished into various shapes to display a cats eye effect. Satin Spar acts like fibre optics and allows light to pass through making it an excellent material for lamps.

So have a look at your piece of “Selenite”.  If it is clear and flaky then you have Selenite.  If it is fibrous and looks like silk, it is Satin Spar.