XRF "milliprobe"
Spot Analysis and Elemental Mapping

A sample of the Deer Isle Granite from Maine, 30 millimeters in diameter (6X magnification). Notice the zoned feldspar crystal in the lower right center of the area outlined by the red box (which is approximately 14.6 mm wide by 9.7 mm high).

A grid of 14 x 11 one-millimeter diameter spots (154 total) were analyzed within the boxed area (deltaX approx. 1.12 mm, deltaY approx. 0.97 mm), from which element maps were produced.

Below are element maps for the major elements found in feldspars: Si, Al, Ca, Na, and K. Clearly there is significant chemical zoning in this mineral crystal!

Si
Al
Ca
Na
K

Below are element maps for the other elements, not typically found in feldspar. Peaks in their abundance are probably the result of included minor or accessory phases (e.g. P + Ca is probably apatite; Fe + Ti is probably ilmenite)

P
Mg
Mn
Fe
Ti