MAGIC STONES AND ELECTRIC GEMS 31
Redondo Beach were found, in 1901, in an Indian grave, where they were probably placed as amulets for the dead.50
The
occurrence of fluid cavities in quartz, chalcedony, sapphire, and other
minerals, is due at times to cavernous structures formed during the
growth of these minerals, when the crystalline substances, for some
reason, instead of filling these up solid, will avoid the caverns and
enclose the liquid of crystallization. In agate inclusions this is
found with silicious content, possibly due to the fact that it is to an
extent carbonic acid gas, or water containing salt or some other
foreign substance. In agate chalcedony, whether in pebbles as minute as
a pinhead, or in amygdules several feet across, the liquid is enclosed
because the walls of the gas-pores in the rock, which are frequently
almond-shaped, are gradually becoming smaller, or rather the walls
thicken by the deposition of the silica forming agate, chalcedony, or
any impenetrable layers, or else an impenetrable form of quartz; then
again, frequently toward the centre or when the liquid forms less
rapidly, or through some change, the quartz becomes crystalline, either
colorless, smoky, or amethystine, and this is due to various
inclusions. This gradual thickening of the walls means that the
aperture into which the liquid penetrates becomes smaller and smaller
until at last it is entirely sealed, so that it becomes enclosed in a
kind of nature's water-bottle, these being sometimes as large as in the
chalcedony specimens from Uruguay ; this is also the case with the
hydrolites and the enhydros, when they can be shaken and the water
rattles as in a bottle.
An occasional small Redondo Beach, California, or Med-ford, Oregon pebble contains a moving bubble of air in liquid.
"
George Frederick Kunz, " Gems, Jewelers' Materials and Ornamental
Stones of California," California State Mining Bureau, Bulletin No. 37,
Sacrar mento, 1905, pp. 71-73.
