Diamond Searching by Specific Gravity

By: 
Waymon Cox
 Updated: 
Jasper
Jasper

Greetings from Crater of Diamonds State Park! When digging dirt to sift for diamonds at the park, finding certain other minerals can make your search more productive. Look for locations where running water has carved a path through the plowed dirt of the diamond search area. As water from runoff and other sources wash through the field, it picks up heavier materials and sediments. Ditches and other natural drains often serve as traps to catch diamonds and other heavy minerals, making them more favorable places to dig.

Garnet and Chrome Diopside

Diamond has a specific gravity of 3.52, which means that it is about three-and-a-half times heavier than an equal volume of water. Minerals with similar specific gravities are often found near one another, due to erosional forces moving materials through the diamond search area.

heavy gravel

One of the most common to look for at the park is jasper, a silicate mineral with a smooth, rounded surface and waxy luster. It comes in many different colors—including red, yellow, orange, and brown—that make it very noticeable in the park’s black and green volcanic soil. The specific gravity of jasper ranges from 2.5 to 2.9, with most jasper found at the park on the lighter end of the spectrum.

Calcite is another mineral you can look for in areas with lots of jasper. Calcite from the park typically appears as a small, white crystal with a flat and blocky shape. The specific gravity of calcite is 2.71. Calcite is very soft and easy to identify by scratching it with a pocketknife or fingernail file.

While the previous two minerals are easier to find, there are others with a specific gravity closer to diamond that are less common. One that many diamond hunters love to find is garnet, a glassy, transparent mineral with a purple to a pinkish hue. Look carefully, because most garnet from the park is very small. They are often tiny enough to get stuck in the bottom of a fine sifting screen! The specific gravity of garnet ranges between 3.1 and 4.3, close to that of a diamond.

Another favorite is chrome diopside or verdelite. This typically-small mineral has a bright, lime green color that makes it easy to spot. Out of this list, chrome diopside has a specific gravity closest to diamond, ranging between 3.25 and 3.55. This means that if you find chrome diopside in a heavy gravel deposit, flowing water could have carried a similar-sized diamond to the same area.

While searching for minerals with a higher specific gravity won’t guarantee a diamond find, it can help you locate areas where you are more likely to find a diamond. You can also build a collection of these other minerals to help others learn what to look for in their own diamond search!

Search area last plowed: October 9, 2019

Most recent significant rain: November 11, 2019

Diamond finds for the week of November 3, 2019 (100 points = 1 carat):

November 4 – Nathan Tompkins, Jonesboro, AR, 8 pt. white; Daniel Van Crump, Wiggins, MS, 5 pt. white; John Heiken, Paradise, CA, 23 pt. brown, 37 pt. brown

November 6 – Larry Taylor, Fayetteville, WV, 2 pt. yellow, 9 pt. white; Sam Jones, Fayetteville, AR, 24 pt. yellow; Daniel Van Crump, Wiggins, MS, 1 pt. yellow

November 7 – Larry Taylor, Fayetteville, WV, 18 pt. white

November 9 – Jason Barr, Woodlawn, TX, 6 pt. white