Silica
Silica also known as silicon dioxide is well known for being a very hard substance. It is most commonly found in sand or quartz and is the main ingredient in glass. Silica is also the main component of many of the bead releases that we dip our mandrels in!
Inhaling silica dust
(copied from Wikipedia!) Inhaling powder of any kind (other than prescribed medicines) is not recommended. When considering potential inhalation effects of silica, it is important to understand whether the silica is crystalline (such as quartz) or amorphous (non-crystalline). See the structure and properties section below for more information on which forms are crystalline and non-crystalline.
Inhaling finely divided crystalline silica dust in very small quantities (OSHA allows 0.1mg/m3) over time can lead to silicosis, bronchitis or (much more rarely) cancer, as the dust becomes lodged in the lungs and continuously irritates them, reducing lung capacities (silica does not dissolve over time). This effect can be an occupational hazard for people working with sandblasting equipment, products that contain powdered crystalline silica, and so on. Children, asthmatics of any age, allergy sufferers and the elderly (all of whom have reduced lung capacity) can be affected in much shorter periods of time.
In studies across Europe (Britain/France) amorphous silica has been found to be biologically inert when ingested and inhaled. Warheit ET Al found during that their bio assays that any minimal damage was reversible. In the USA the Food and Drug Administration has found it to be exempt from normal process and it is allowed in food and medicine.
Silica is harmless in other forms it is purely inhalation that can be detrimental to health.
Don't be scared!
this information is not intended to scare people but simply to highlight the fact that many of the things that we use in lampworking and jewellery making need to be treated with respect being aware of potential side effects will facilitate that!