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Geology/What kind of rock is this?


I found this rock a while back at Beverly beach in the tide caught on some seaweed. This rock has pores in it but almost all of them are filled with some kind of crystal and it has one section where it's completely covered in crystals.

Always tricky to do identification from a picture. If the white part fizzes with strong vinegar then you might have a piece of volcanic rock with calcite inclusions in the vesicles or hollow spaces. Another possibility would be zeolites. These are hydrated silicates, white in color, that often fill holes in volcanic rocks.
Without some physical testing this will be hard to tell. We do free identification at our university as an outreach program. If you are interested, here is the link:


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Uwe Richard Kackstaetter, Ph.D. (Dr.K)


I can answer questions concerning minerals, mineralogy, gems, metals, groundwater, national and international geoscience field trips and anything that has to do with geology. As a public service and part as training for new geoscientists, our university department provides detailed FREE mineral identification for individuals with available non-destructive and destructive analytical procedures and a several page report. Please contact me for details or go to for details..


I am a professor of applied geology and mineralogy with many hours of field experience. Furthermore, I enjoy recreational gold prospecting and mineral collecting. As a professor I am engaged in research concerning minerals, their identification and their occurrence. I am currently developing inexpensive, accurate mineral identification procedures to be used by experts and lay people alike.

Member of the GPAA (Gold Prospectors Association of America) as well as the Association of Environmental Geochemists. Member of the GSA (Geologic Society of America) Member of the AIPG (American Institute of Professional Geologists)

Here is a small sampling: Mineral-rock handbook: Rapid-easy mineral-rock determination : written for anyone interested in minerals and rocks - Proctor, Peterson, and Kackstaetter;Macmillan Pub. Co. (New York and Toronto and New York) Physical Geology Laboratory e-Manual with 20 Lab Exercises [now available for FREE]: Colorado Front Range Self-Guided Geology Field Trips [FREE download] Kackstaetter, U.R. (2014): A Rapid, Inexpensive and Portable Field and Laboratory Method to Accurately Determine the Specific Gravity of Rocks and Minerals. The Professional Geologist, Vol. 51, No.2, AIPG. Kackstaetter, U.R. (2014): SEDMIN - Microsoft Excel (TM) spreadsheet for calculating fine-grained sedimentary rock mineralogy from bulk geochemical analysis. Cent. Eur. J. Geosci. DOI: 10.2478/s13533-012-0170-3

Ph.D. in Applied Geology and Mineralogy. I am actively teaching courses in mineralogy, igneous & metamorphic petrology, applied volcanology and a variety of national and international field courses with mineral collecting opportunities. Background in precious metal exploration and groundwater (hydrogeology).

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