J. Michael Howard answers questions about Diamonds
A. Dear Liz,
You have a good question. There has been a lot of confusion over the name "Arkansas Diamond" because of two things: there are real diamonds that are found in Arkansas, and then there is inexpensive quartz crystal jewelry that is sold in tourist shops under the name "Arkansas Diamond" and "Hot Springs Diamond", which is a local name for faceted quartz crystal.
The easiest (and possibly the fastest) way for you to know if your mother has an authentic diamond or a quartz "Arkansas diamond" is to take it to a reputable jeweler and pay a small fee to get it identified. There are several non-destructive tests. One, based on optical properties, measures the indices of refraction (a function of the speed of light in the mineral). These are entirely different for quartz and diamond. The other test is a measure of the surface conductivity of the mineral. This test is done by using a small battery-powered electronic instrument with a probe that touches the stone and indicates yes or no if the stone is a diamond. Many pawn shops have this instrument to help them determine what the stones are in gold settings.
Also, you should clean the piece of jewelry and then look inside the band. Does it have a carat marking? If so, what is it? 10 or 14 carat (it will say 10 Kt or 14 Kt)? If it is set in solid gold, not gold plate or base metal, it may be a clue indicating a real diamond, because inexpensive stones are rarely set in expensive (10 Kt or 14 Kt gold) settings.
You might ask to look at the stone under a microscope or jeweler's loupe. If you see wear on the girdle (rim between the top and bottom) or crown of the stone (tiny frosted patches or numerous scratches on the edges between the flat faces, you do not have a diamond. A diamond is hard enough that nothing other than another diamond, will scratch it. Quartz is the most common of the harder minerals, but with the passage of time and normal wear, it will display some scratches and dings. If it is a diamond, it may display some small inclusions or spots. These spots may be black or look like colorless individual or patches of icicles suspended in the diamond. Quartz usually has few if any flaws, because due to the low price, the cutter looks for water clear flawless pieces .
Even if your mother did not get a real diamond given to her, she can wear the stone and really enjoy it! Arkansas diamond is not expensive (or particularly valuable dollar-wise), and many folks who visit the Hot Springs area buy some jewelry set with quartz crystal. I know that gift shops in Hot Springs and the Coleman's Rock Shops (connected with the quartz mining operations) in Hot Springs and Jessieville, sell a lot of this type of costume jewelry. One of the prettiest necklaces I ever bought for my wife was composed of hundreds of faceted quartz crystal beads.