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[Rare eBooks] Gemstones and Their Distinctive Characters


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New in our Digital Antique Books Library…

Gemstones and Their Distinctive Characters
by G. F. Herbert Smith, 1912

This 1912 book is one of the foundational books for gemology. At 364
packed pages this is worth its weight in gold, or
An essential read for all gemologists, and goldsmiths,
jewelry store staff etc. It lays out the principles and science of
gemology. Any jeweler would find it interesting and it belongs in
every gemologist’s library. The myriad stories about gems, history
and rumour are really intriguing.

Very solid, wonderful illustrations and images. A truly important
book. It was written in response to a burgeoning variety of
imitations, fakes and the beginnings of synthesized materials. An
attempt was made to make the science understandable and transparent,
not to be just the jargon loaded `incantations of a wizard’ for an
average person.

The table of contents is huge.

The book is broken into several discrete chapters and sections.

The Characters of Gemstones: Crystalline form, reflection,
refraction and dispersion, measurement of refractive indices, luster
and sheen, double refraction, absorption effects: color, dichroism
etc, specific gravity, hardness and cleavability

The Technology of Gemstones: Unit of weight, fashioning of
nomenclature of precious stones, manufactured stones,
imitation stones.

Precious Stones: Diamond, occurrence of diamond, historical
diamonds, corundum, beryl.

Semi-precious stones: topaz, spinel, garnet, hessonite, pyrope,
rhodolite, almandine, spessartite, andradite, tourmaline, peridot,
zircon, chrysoberyl, quartz, chalcedony, agate, opal, feldspar,
turqoiuse, jade, spodumene, iolite, euclase, enstatite, diopside,
sphene, cassiterite, obsidian (and a bunch more I did not include
here).

Ornamental Stones: Fluor, lapis, sodalite, violane, rhodonite,
azurite, malachite, thulite, marble, aposphyllite, crysocolla,
steatite, meershaum, serpentine.

Organic Products: Pearl, coral, amber.

Tables: chemical composition of color of gemstones,
refractive indices of

Gems: color dispersion of character of the refraction of
dichroism of specific gravities of gemstones,
degrees of hardness of data.

There is a very good index.

The introduction discusses the role of fashion in gem valuation. The
science discussed is really well advanced. The refractometers and
polariscopes shown are very early indeed and let the modern
gemologist know how far we have come. There is a quite a bit of math
and calculation shown for those with that bent. There are oddities,
like the luster scale only consisting of 3 steps, so one can see how
was incrementally added to the field. Absorption spectra
are discussed, far earlier than I thought they had been addressed.
Specific gravity testing in its forms, including things not used any
more, like a `diffusion column’, a single tube with the lighter sg
liquid poured over the heavier, and then known pieces of different
specific gravity added. The unknown stone will float between the
known ones and so can be diagnosed as a certain range. Interesting.
The thallium use descriptions are very thorough but it is not to be
used today except in stringent lab conditions as it is too
dangerous. Another odd test is for electrical properties by blowing
a mixture of red lead and sulfur powder through a sieve onto a stone
which gives it static electricity, the different colored powders
self separating to the ends of the crystal (or stone) accorded to
their charges. Tourmaline, for instance is extremely strong this
way.

There is a really intriguing history of weighing gemstones and the
unification of the carat standard, as there were more than a dozen
different weights all using the word carat used in different places.

There is an excellent history of cutting The chapter on
nomenclature and where gemstone names came from is very good. There
is a wonderful section on the history and introduction of man-made
gems, ruby as early as the 1830’s and in the 1880’s a large volume
of reconstituted rubies came on the market. Verneiul’s machine came
into use in 1904, earlier than I had thought.

There is exhaustive on diamonds. History, material, and
insight into the predatory struggles in South Africa for supremacy
in the industry. The sections on all the individual gemstones are
excellent, lots of stories and details not seen often elsewhere. Let
us just say that most gems are dealt with, and very well at that. A
modern gemologist could learn a lot from them, as would a jewelry
store sales person. It is interesting how most of contemporary
gemology is the same as then, that they knew so much already. The
biggest changes since then have been sprectroscopy, synthetic gems,
irradiation. All of this is a huge part of the book.

Besides all the science this description of pearls sums up the
literary flavor of the book: “From that unrecorded day when some
scantily clothed savage seeking for succulent food opened an oyster
and found to his astonishment within its shell a delicate silvery
pellet that shimmered in the light of a tropical sun, down to the
present day, without intermission, pearl has held a place all its
own in the rank of jewels.” The stories of famous gems, their costs
and more cannot be found elsewhere.

The tables are good, but a bit minimal by today’s standards.

This book is highly recommended for anyone’s collection.

File Size: 27.3MB, 364 Pages

Download the full eBook at the ridiculous price of $5.