Stories surrounding the rocks

 kw: book reviews, nonfiction, rocks, minerals, stories, legends, surveys

This is a shelf of my own Lapidarium (rock collection), chosen for its variety. If you click on the image you can see a larger version.

As a rock collector I have eclectic tastes. Here are minerals, fossils, sliced-and-polished geodes, and a few crystal clusters that were grown in a jar (such as the deep blue at bottom center: copper sulfate, which occurs in nature in very arid regions as the water-soluble mineral chalcanthite).

The word "lapidarium" is quite obsolete, but is found, very fittingly, in the title of a recent book, Lapidarium: The Secret Lives of Stones by Hettie Judah. Ms Judah writes primarily about art, particularly the stories surrounding artworks; here, the artworks are natural stones and modified stones.

Sixty stones, loosely so-called, are surveyed in six sections, with the themes Power, Sacredness, Evocativeness, Technology, Sculpture, and Life. Life? Consider Coral. In a game of Twenty Questions, the answer to the obligatory opening question, "Animal, vegetable, or mineral?" is "Yes" or "All". The polyp animal, bearing symbiotic algae in its tissues, secretes a mineral skeleton. The deep red skeleton of precious coral, so sought after by kings of old, is colored by pigments derived from the algae. You can only get away with this once.  The Life section also mentions Pearl and Blue Lias; the latter is a heavily fossiliferous shale on England's Jurassic Coast. A few examples from the other sections:

Power: Powerful people like gemstones such as emerald, ruby and sapphire. Note that ruby and sapphire are both corundum (aluminum oxide), with different minor impurities that confer their colors. So this is clearly not a mineralogy book. I firstly thought that Old Red Sandstone was an odd choice; it turns out that the famed Stone of Scone, where Scottish kings were anointed, is a big block of Old Red Sandstone.

Sacredness: Pele's Hair, a type of spun glass from volcanic lava fountains, is sacred to the Hawaiians. Sarsen is silicified sandstone (much tougher than the usual calcite-cemented sort) that makes up the larger stones at Stonehenge. Cinnabar, or mercury sulfide, is a bright red mineral that was used to make scarlet pigment for cosmetics and the clothing for royals and ecclesiastical officers (and poisoned a number of them). Tuff was used to form the Moai, the standing sculptures on Rapa Nui (AKA Easter Island). I must mention that, while the article mentions a study in 1997 of moving one of the statues using ropes, a sledge, and banana-juice lubricant, the moai actually "walked". See this 2013 video. It is a clip from a longer presentation.

Evocativeness (the section is called Stones and Stories): Lapis Lazuli, translated "azure-colored stone", was also a stone of power, but later became better known as the source of Ultramarine pigment for the intense blue and indigo colors in paintings of the great masters. Phonolite Porphyry is a "ringing stone" that makes up the substance of Devil's Tower in Wyoming. Tap a piece with a smaller stone and it will ring like a gong or bell. So will most of the Dolerite stones that make up the inner circle at Stonehenge, and there is a field of ringing stones in eastern Pennsylvania.

Sculpture: Gypsum (usually as alabaster), chalcedony, onyx, and crystalline quartz are among the stones favored for carving and sculpting into artworks. Red Ocher, a mix of red hematite and other iron oxides, may have been used for art tens of thousands of years ago, both as a pigment and as a material to sculpt.

Technology: Flint may be the basis of the oldest technology, that of making edged tools of stone by knapping; the article is mostly about a modern flint knapper who became so skilled, many museums have his counterfeits on display. Obsidian may be equally old, but its occurrence is not as widespread. Lodestone, magnetic ferrous (Iron II) oxide, appears to have a nearly 1000-year history as an aid to navigation. Coltan, an ore containing niobium (columbium) and tantalum, is still in heavy use for electronics. Mica, particularly the clear, colorless form called muscovite (named for Moscow), was used for oven door windows because it is heat resistant; in such a use it was called Isinglass.

This is a fun, well-written book, not about rocks per se, but about stories about rocks.