Fire Agate Rough Windowed Preform Gemstone 113 Carats Slaughter Mountain AZ SLP004

This large preform fire agate gemstone measures 37.54 by 30.14 by 15.57 mm and weighs 113.2 carats. The stone has been trimmed of excess material, carefully freeform contoured cut and then roughly polished to help display the internal fire structure. The initial top fire layer is currently showing the normal first layer that is often found in Slaughter Mountain material, an orange crackle style fire. Upon close examination with a jeweler’s loupe, it shows a rainbow mixture of different fiery colors deeper within portions of the stone. One side of the preform shows a multitude of stacked limonite fire layers and a unique sagenite crystal spray. This stone has good carving possibilities for a talented freeform carver, with either one large gemstone possible or three different stones if the various aspects are separated into different pieces.

This piece of fire agate rough originates from Slaughter Mountain, Arizona. Renowned globally for exceptional fire agates, Slaughter Mountain gemstones often showcase vivid color ranges including bright reds, oranges, greens, purples and blues. The mineral deposit lies within the San Carlos Apache Indian Reservation and mining rights are exclusively reserved for tribal members.

Photographs were taken indoors under artificial full spectrum lighting and outdoors in natural sunlight, with the stone shown dry and wet to mimic a polished and enhance the visibility of their internal fire. Close-up magnification photos are included to better reveal the intricate fire layers and colors within the stone. The colors in fire agates result from the Schiller effect, like that seen in mother-of-pearl and opals. This phenomenon arises from alternating silica and iron oxide layers that diffract light, creating the color interference known as fire. Optimal light conditions are necessary to fully appreciate this play of color, as the stones appear a darker brownish color and less vibrant in lower lighting conditions.

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