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Ch. 2: Origin of Gemstones

Ch. 1: Introduction Page of 118 Ch. 2: Origin of Gemstones Text size:minus plus Restore normal size   Mail page  Print this page
CHAPTER II.
THE ORIGIN OF PRECIOUS STONES.
Though the origin, formation, composition, character­istics and tests of each stone will be examined in detail when dealing with the stones seriatim, it is necessary to enquire into those particulars of origin which are common to all, in order thoroughly to understand why they differ from other non-metallic and metallic minerals.
At the very commencement we are faced with a sub­ject on which mineralogists and geologists are by no means in full agreement, and there seems just ground for considerable divergence of opinion, according to the line of argument taken. It is a most remarkable fact that, precious as are certain stones, they do not (with a few exceptions) contain any of the rarer metals, such as platinum, gold, etc., or any of their compounds, but are composed entirely of the common elements and their derivatives, especially of those elements contained in the upper crust of the earth, and this notwithstanding the fact that gems are often found deep down in the earth. This is very significant, and points to the conclusion that these stones were formed by the slow percolation of water from the surface through the deeper parts of the earth, carrying with it, in solution or suspension, the chemical constituents of the earth's upper crust; time and long-
Ch. 1: Introduction Page of 118 Ch. 2: Origin of Gemstones
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