Regarding the tenth stone of the Breastplate there is a general disagreement amongst authorities, some preferring simply to give its Hebraic name THARSHISH without attempting its meaning.
The tenth division of the Breastplate is the division of the zodiacal Capricorn, the colour of which is generally regarded as black, the colour of the planet Saturn, and which according to Dr. Simmonite, William Lilly, Madame Blavatsky and others, is, esoterically, green. The Targums describe the stone Tharshish as of the colour of the Great Sea, or sea colour. This is found in the Serpentine variety of a translucent deep green, oily colour capable of receiving a high polish. The colour of the Egyptian and Arabian Serpentine (or HYDRINUS) is deep and a little heavy. Many intagli and camei of antique origin are found cut in Serpentine; these specimens include Egyptian scarabei and Babylonian cylinders of about 5,000 years ago, clear evidence that the ancients knew the stone, appreciated it and worked it.
The sign Capricorn is a strange one, symbolizing the Gateway of Heaven through which men pass when life on earth is done. Hence it expresses the mystery of the deep seas which were compared with the seas of space in sacred philosophy. Amongst others, Manilius recognizes Capricorn as a sailor’s sign:
But when receding Capricornus shows
The star that in his tail’s bright summit glows,
Then shall the native dare the angry seas,
A hardy sailor live, spurning inglorious ease.
Rev. Mr. King writes of a cast from a gem engraved with a “double-headed Capricorn with an owl’s body standing upon and holding in his forefoot a rudder: in allusion to the doctrine laid down by Manilius that the star in the sign’s tail is the proper horoscope of mariners and pilots. Or it may typify the usually fickle temper of one born under the sign. This sign likewise presided over all the space within tide-mark, the alternate domain of sea and land; a dominion expressed by the half terrestrial, half marine composition of the figure. The region peculiarly under him” (that is, the region astrologically ruled by Capricorn) “was the West of Europe.” (This is speaking very generally.) “The owl’s body is given him perhaps as the attribute of Pallas, the designer of that prototype of navigation, the Argo.”
Godfrey Higgins writes of the “whimsical sign called Capricorn which in the Indian Zodiac is an entire goat and an entire fish: in the Greek and the Egyptian the two are united and form one animal.”
The place of dazzling brilliancy, called by the Greeks “The Milky Way” is the path of the souls, and is referred to by Macrobius, Cicero and other writers. The author of the “Anacalypsis” writes: "The Milky Way is placed immediately under that degree of North Latitude which is called the Tropic of Cancer, and the two tropics of Cancer and Capricorn have been called by the astrologers “The Gates of Heaven or the Sun,” at each of which the Sun arrives in his annual progress. The Southern Gate is called the Tropic of Capricorn, an amphibious animal, half goat, half fish in our present zodiacs, but in the most ancient zodiacs of India it is described as two entire beings—a goat and a fish. Here, in this goat-fish sign Capricorn, are the mermen and mermaids, and the half-animal, half-fish beings of the sea. Of the tribe of Asher it is said: “Out of Asher his bread shall be fat, and he shall yield royal dainties,” (Gen. 49. 20), a statement very much in agreement with the sign Capricorn. Again in Deuteronomy (33. 24) we have, according to the Authorized Version, “Let Asher be blessed with children: let him be acceptable to his brethren, and let him dip his foot in oil”; this passage, however, may be closer translated as follows: “More than all the children be Asher blessed: he shall be the most favoured of his brethren and bathe his feet in oil.”