Food For Thought title

Ruby, Sapphire & Emerald Buying Guide
by Renée Newman
© 2000, International Jewelry Publications, 164 pp., US$19.95

Cover photo  

This book is one of Renée Newman's popular series of buying guides designed for retail buyers of gems and jewelry.

The book is divided into 16 chapters that discuss the various aspects of these stones. An appendix lists the properties and sources of these gems, and a bibliography is also provided, along with a brief index.

Major plusses

A number of features recommend this book:

  • Unlike so many books which purport to teach people about this most visual of fields, the author understands the importance of good illustrations. Virtually every concept is well-illustrated, either in photos or with line drawings. The color reproduction of photos is excellent throughout.
  • Again, unlike many consumer books, the Ruby, Sapphire & Emerald Buying Guide contains a good bibliography, along with some in-text references. This is of particular use for those wishing to delve deeper into the subject, and is greatly appreciated.
  • Each topic is discussed in great detail.

Minor quibbles

Like all books, there are the occasional errors or misstatements.

  • On p. 21, specific gravity is described as "the ratio of a gem's density to the density of water." It would be more correct to state it as a ratio comparing the weight of a gem to the weight of an equal volume of water at 4°C.
  • Terms are occasionally introduced before they are fully defined. For example, the weight estimation formulas on p. 24 refer to the term "girdle" but it is not defined until p. 27.
  • The section "How to Examine Color" on p. 44 makes no mention of rotating the gem during examination. This is crucial to take into account problems with asymmetrical cutting and color zoning, as well as inclusions which might be visible from only one direction. One has to reach p. 76 before this important factor is introduced.
  • The section "How Lighting Affects Ruby Color" on p. 45 states that reds are enhanced early and late in the day. While this is true of direct sunlight, no one examines gems with that lighting. People use skylight, which is actually at its most blue early and late in the day. Similarly, the statement that overcast skies add blue is again incorrect. Clouds produce a more white skylight (which is why they appear white, not blue).
  • Color descriptions throughout the book are largely two-dimensional, i.e., they attempt to describe all color variations solely in terms of shifts in tone or hue position (for ruby, either more orangy or purplish red; emerald as more bluish or yellowish green). Only occasionally is the concept of saturation (described as color purity throughout the text) discussed in reference to quality. While this "saturationless" approach to color description does mimic the terminology used by many gem dealers, it is not a proper foundation upon which to build a good understanding of color science. Saturation is the most important of all gemstone color attributes and is not given its due in clear enough terms.

If there is any one flaw in this book, I would say that for the target audience, it is a bit overwhelming. So much gemological information is packed into the 164 pages that beginners may feel adrift on a giant technical sea. But this is a small complaint. There is also much to commend. Overall, the Ruby, Sapphire & Emerald Buying Guide succeeds admirably in its goal of offering sound advice for the purchaser of ruby, sapphire and emerald. The reader cannot fail to learn much about gems. My hat is off to Renée Newman for another rousing success.

Reviewed by Richard W. Hughes
RWH Publishing & Books
Reviewed May 2000


Renée Newman comments:


Thank you for your kind words about my new ruby, sapphire and emerald book. You brought up some interesting points. I agree with your first three minor quibbles. I question your fourth and need to do more research before I comment on it.

I disagree that I have a two dimensional, "saturationless" approach to color description. I define my three-dimensional color terminology on page 39. When I describe the evaluation of ruby and emerald color on pages 41 and 51, I begin with saturation. But I describe it in terms any dealer or consumer could understand. Regarding emerald, I state, "pure colors are more desirable than dull, muddy ones. In high quality emerald, the bright areas of color should not look grayish or brownish."

When I describe high-quality Mogok rubies on page 47, I included the statement: "There is hardly any brown or gray masking the hue. (In other words, there is a minimal amount of brown or gray present. Consequently, the color of the stone is a more intense red.)" I find this easier for my readers to understand than saying good Mogok rubies have a saturation range of X to Y%. Furthermore, I don't know of any studies that have measured their saturation range and I doubt that dealers would be able to agree on a range.

I also include the concept of saturation in my color description of the various sapphires. I normally use terms other than "saturated" to describe it because I've found that "saturation" (along with intensity, strength and richness) has a variety of meanings. Some people use it to refer to tone, some to the amount of gray or brown present, and others to both tone and saturation. I find the term "color purity" to be less ambiguous, especially in the contexts in which I use it. But I agree it's not the best term since it can also refer to the hue. If any one can come up with an unambiguous term for "saturation" that would be clear to the general public and the trade, I would appreciate hearing about it.

The reason I've packed so much information in this books is because it's written for the trade as well as for consumers. Salespeople, dealers and appraisers want comprehensive reference materials; pawnbrokers and antique dealers want easy-to-read identification information; serious gem buyers want complete evaluation data. My book, the Gemstone Buying Guide, is ideal for people who want a more general and less technical book.

Thank you for including the cover photo and flattering review of my book on your website. Congratulations on creating what is probably the most informative and entertaining gemstone website on the Internet.

Renee Newman

Page updated April 26, 2006
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