Diatomite

Diatomite forms when the silica shells of diatoms, single-celled algae, pile up on lake and sea floors and turn into rock. It is a white or beige, very light rock that crumbles in the hand; ground to a fine powder it is used to filter liquids, as insulation and as a mild abrasive. According to USGS data, Türkiye is among the world's largest diatomite producers.

Filtering: The largest use; according to a Turkish source about 60% of world consumption goes to filtering beer, wine, sugar syrup, oils, drinking water and pool water. According to the USGS it is also used in public water systems to remove bacteria and protozoa. Absorbent and carrier: It soaks up liquids and oils quickly and is used in cat litter, as a carrier for farm chemicals and as a feed additive. The filler that absorbed and steadied the nitroglycerine in Nobel's dynamite was diatomite too.

It has a hardness of 1.5 on the Mohs scale. It is soft enough to scratch with a fingernail. Its specific gravity is 0.32–1.38 g/cm³.

Its best-known localities: Island of Fur, Limfjord, Denmark; Lompoc, California, USA; Hırka, Kayseri, Türkiye; Lüneburg Heath, Lower Saxony, Germany; Lake Mývatn, Iceland.

Known localities in Türkiye: Hırka, Kayseri, Türkiye; Karacaören, Ürgüp, Nevşehir, Türkiye; Alayunt Basin, Kütahya, Türkiye; Ihlara–Selime plain, Aksaray, Türkiye.

It is very light, and when dry it crumbles easily in the hand; the colour is white, off-white or beige. It looks like chalk but is clearly lighter. It does not fizz in dilute acid or vinegar, which separates it from chalk and limestone. Its powder feels slightly gritty between the fingers, like pumice powder. It soaks up water like a sponge: untreated diatomite can hold three to four times its own weight of water. Chalk, kaolin (white clay) and pumice powder can look like diatomite. Chalk fizzes in acid; clay turns plastic and sticky when wet.

On the “street to diamond” value ladder it sits on step 3 of nine: Building and industrial stone. Diatomite is a cheap industrial raw material sold by the tonne, and its value depends on how pure it is for the intended use. As a filter material it needs a high silica content (at least 85% according to one Turkish source), very little iron and clay, whiteness, high porosity and a suitable particle size; heat treatment (calcination) improves its filtering quality. The thickness of the bed, thin overburden, ease of mining and the distance from the quarry to the user also matter. For ordinary uses such as insulation and light fillers, simply processed diatomite is enough and much cheaper.

On social media and among sellers of herbal products it is claimed that swallowing diatomite powder kills intestinal parasites and flushes heavy metals out of the body. Among farmers, diatomite powder fed to livestock is believed to be a natural remedy against internal parasites (worms). The fact-checking organisation Science Feedback finds no evidence that diatomite removes parasites or heavy metals in humans. In two studies on cattle, the groups given diatomite did no better than the control groups. Diatomite powder should not be swallowed or inhaled; the heat-treated kinds made for pool and industrial filters in particular contain crystalline silica. This section reports beliefs; it is not health information. There is no scientific evidence for these claims and no stone replaces medical treatment.

Avoid breathing diatomite dust. Natural (untreated) diatomite is mostly amorphous silica, but heat-treated (calcined) pool-filter grades contain crystalline silica, which can cause the lung disease silicosis after long exposure. The USGS also notes that many forms of diatomite contain crystalline silica, which is known to cause cancer and reproductive harm above permissible exposure limits. Wear a dust mask when working with it.