Size/Shape

Cutting

Proportions

Color

Clarity

Origin

Treatment

Weight

9.0 x 9.0mm 'Square' Octagon

Precise Step-Cut, High Polish, No Nicks or Scratches

Depth 6.8mm, Full Brilliance, No Windowing

Attractive Yellowish-Green in Daylight

Light Yellow-Brown in Incandescent Light

V. Slightly Included

Kayes Region of Western Mali, West Africa

Not Treated, 100% Natural

3.93 Carats

Faceted by a skilled and experienced lapidary artist, this large Prehnite was cut from a selected piece of rough recently mined in Mali.

Normally 'cloudy' or 'silky' in appearance, Prehnite is considered a stone useful only for producing cabochons or carvings.  A small percentage of the rough is, however, clean enough to facet into attractive gems.  With a hardness of 6 - 6.5 and no significant cleavages, the stone is durable and takes a good polish as well.

The translucence of this octagon is high compared to most Prehnite from Mali.  The color is unusually green, and we noticed a slight color-shift from green to brownish-yellow in incandescent light.

Through a Chelsea Filter, this stone is pinkish-red.  Thinking that Chromium might be present, we sent a sample of this material to the GIT laboratory.  The result of the analysis was the detection of Vanadium.

Below are some links to information about the mineral Prehnite.

Prehnite Information from Mindat.org

The photos show the attractive green color of this Prehnite using cool 'daylight' bulbs.  The result of incandescent lighting is seen, showing the shift to brownish-yellow color.

As always, none of our images are 'photoshopped' with any modification of contrast, brightness, tone, saturation, or hue.

This stone is slightly included, but the cutting is fantastic and the color, resulting from the Vanadium content, is strong and pleasing.