Month: October 2019

Rare Large Jasper Nodule from the Carver Agate Field

Rare Large Jasper Nodule from the Carver Agate Field

This posting is more about geology than a pretty specimen. Bear with me as I ‘get into the weeds’ to explain why this is rare and is the subject of this posting. How nodules form Gas bubbles in molten lava sometimes, after hardening, leave a bubble or void in the hardened lava which may fill with a silica solution. The silica often creates banded agates or crystal lined voids in the center of the nodule which are called geodes. What is rare and unusual in this large specimen, is that the nodule formed in the gas bubble is essentially jasper, not agate, quartz, or other crystals.  While The Carver agate field has lots of jaspers, they are almost always formed separate from, and outside of, gas bubbles that have formed in the lava. The process by which jasper would completely fill a large gas bubble is apparently uncommon. I have […]

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Odd-ball Geodes from the Carver Agate Field

Odd-ball Geodes from the Carver Agate Field

This green geode is notable because green is a fairly rare color for nodules and geodes found in West Texas. The salmon/orange-colored geode below has an unusual rind surrounding the crystal-filled hollow center of the stone. While these finds are not ‘spectacular,’ they are geologically interesting to serious rock collectors and discovering them would make any collector’s day!

West Texas Baconite from the Carver Agate Field

West Texas Baconite from the Carver Agate Field

This pink and white banded agate looks like a bacon slice and so that is the name I gave it. The upper edge of the ‘baconite’ contains petite quartz crystals–technically euhedral quartz crystals–that formed in the center of a geode of which this is a part. The outer rind of the geode is seen at the bottom edge of the ‘baconite’ specimen.  

Brecciated Jasp/Agate from The Carver Agate Field

Brecciated Jasp/Agate from The Carver Agate Field

The Carver has produced red and yellow jaspers, sometimes mixed with green.   Yellow and red are seen in this photo.  After the jasper had initially formed, volcanic forces cracked/fractured the jasper into angular shards. Eventually a silica solution in either a liquid or semi-liquid state filled the fractured shards and then hardened, cementing the jasper back together.  These shards that are cemented back together are called brecciated.  Since some of the silica filling in the areas between the shards took on a banding (see particularly the upper left corner of the stone), we see a fortification agate which has formed within the brecciated jasper. For this reason, this specimen can be described as jasp/agate (part jasper, part agate) which is brecciated.