Mineral trivia

[Turned up by Bing; what appears to be a row of teeth in a bit of a state. Amalgamfüllungen. Zähne mit insuffizienten Amalgamfüllungen, die sog. Amalgamstraße. Amalgam -eine Mischung aus Quecksilber und Silberfeilung- wird von der gesetzlichen Krankenkassen immer noch als Standard-Füllmaterial für Füllungen im Seitenzahnbereich empfohlen. Weitere Informationen über Amalgam]

Reference 1, noticed at reference 2, continues to provide entertainment from the margins. The crop below from Tuesday, from the margins of bread batch No.749.

First, coming across the word, possibly in the context of refining the ores of metals, I started to wonder about the origin of the word 'amalgamate', which I use fairly often in the sense of bringing two things together, mixing them together, producing a unified, homogenous whole from two or more parts. As in mixing the ingredients to make a bread dough - although I don't recall ever using the word in that particular context.

Off to OED, which devotes around three columns, spread over two pages, to the word and its variations. It seems that it an old word, around since the time of the Romans, possibly derived from either Greek or Arabic, and that it started out meaning to soften one thing by mixing it with another, typically using mercury to soften or dissolve another metal. Gradually, usage generalised to include any intimate mixing of two or more parts to make a new whole.

The alchemists of old were very into mercury and its amalgamations in their quest for gold. A technique which remains respectable when refining the ores of various metals.

I couldn't see anything in OED about dental amalgam, but Wikipedia at reference 3, talks of 1,500 years ago in China, 500 years ago in Germany. It also points to ongoing controversy about its possible toxicity.

Second, coming across load-stones and lode-stones, magnetised stones which can be used as a crude form of compass, as described at reference 4. The point at issue being where did the word come from? Neither 'load' nor 'lode' seem to have much to do with either magnets or compasses. Off to OED again, to find that load and lode were originally words meaning path, track or water-course. Or something which took you on your way; a conveyance, cart or carriage. Then something which you put on your cart, a load and so to the various current meanings.

Lode survives both in the fen country of East Anglia and Lincolnshire as an open field drain and as a term which miners use for a vein of some valuable mineral, usually metallic. One hears of mother-lodes, for which see reference 5. And as a term for a stone which leads you on your way, the lode-stone with which we started.

Third, the new-to-me concept of double refraction, whereby an incident beam of light is split into two parts, rather than just bent. Rather than just being split into constituent colours in the way of a prism. It seems that some crystals of calcite do this, sometimes called Iceland spar. With such crystals often being toys for aristocratic ladies. With ordinary calcite being common enough. But according to reference 6, all to do with polarity rather than wavelength. While according to reference 7, calcite is a modified, crystalline form of chalk.

References

Reference 1: An introduction to the mineral kingdom – Richard Pearl, J. F. Kirkaldy – 1956, 1966.

Reference 2: https://psmv5.blogspot.com/2025/01/kensington-warming-up.html.

Reference 3: https://en.wikipedia.org/wiki/Amalgam_(dentistry).

Reference 4: https://en.wikipedia.org/wiki/Lodestone.

Reference 5: https://en.wikipedia.org/wiki/Mother_lode.

Reference 6: https://en.wikipedia.org/wiki/Birefringence.

Reference 7: https://en.wikipedia.org/wiki/Calcite.