I picked this up over a year ago when the Kindle edition was offered for free. I don't know the author, nor have I had any communication with him about this book or any other matter. I'm a writer of historical romances, among other things; and I have a passing interest in rocks, gems, and jewelry.
Rendel isn't much of a writer, but he tries. The book's casual, colloquial style, complete with references to pop culture (ca. 2012, so maybe ancient history), make it easy reading. Though it gives a lot of information, it's not super technical. And from what I can tell with a little research fact-checking, it's accurate. If there's any serious lack, it's that Rendel didn't include any photos to illustrate some of his points, such as what the different cuts look like or how light behaves inside a diamond.
The text itself is unfortunately rather filled with typos and random, inconsistent Capitalization, especially of nouns. I found this distracting, and along with the lack of illustrations knocked the rating down from a solid four stars to just three-and-a-half.
When he gets into the specifics of buying an actual diamond -- he recommends buying it loose and having it set -- it becomes obvious that he's directing his guide toward the high-end buyer, not the average young couple walking into Zales or Kay Jewelers with as many sparkles in their eyes as are displayed in the glass cases. And that, too, is unfortunate. The wealthy buyer is more likely to head to a trusted professional jeweler and have access to appraisers; the starry-eyed youngsters really need more help and guidance to keep them from making a poor choice or getting bamboozled.
You won't find a whole lot of history of diamonds, and certainly no stories about the truly fabulous gems that capture our imagination and wonder, but this is actually a pretty practical consumer guide, if you can get past the typos. (Most people can.)