World class 7+ lb hyalite opal plate, SLP, Mexico! Fluorescent gem stone N67

Description

Up for sale is a very large and beautiful specimen of hyalite opal from San Luis Potosi, Mexico! It is in good shape and weighs a little over 7 pounds. It fluoresces bright green in shortwave UV light. This specimen also has micro-apatite inclusions in several places that show up as pinkish specks under shortwave UV light. The micro apatite also phosphoresces for a second or two after  the light is shut off. This specimen is easily among the best and largest pieces I have seen from San Luis Potosi. Pictures were taken dry indoors (UV picture was taken with an 11 watt shortwave UV lamp).
Hyalite opal (Opal-AN) is a clear variety of opal, different from most other opal varieties. It is almost always fluorescent (bright green in shortwave UV) and has a strong vitreous luster. The opals from San Luis Potosi formed underground as a result of precipitation of silica from a vapor phase. It is rare to see large examples of hyalite and it usually occurs as a ~1 mm coating on agates, chalcedony, or other opals. Hyalite typically contains less water than other opal varieties, usually around 3 to 8%.
San Luis Potosi has the only large deposit of hyalite opals that often contain orange webbing, caused by iron inclusions. Orange webbing can be found from other locales, but is very rare.
Please note that you will need a
shortwave UV blacklight
to see the fluorescence! Regular blacklights and longwave lamps will cause little to no response. Around 90% of
fluorescent
minerals fluoresce in shortwave UV, while the others are longwave UV fluorescent.
If you have any questions, feel free to ask and I will respond as soon as possible. Also, please check out my other listings!