$145Median
14Sold (12 mo)
$125Last sale
Updated 4d ago
Opal
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Attractive blue bubbly botryoidal crystalline opal-AN across the top of a granite matrix.In the White Oak area of Montgomery County, Maryland, the regional geology is dominated by the metamorphic crystalline rocks of the Piedmont Province, including weathered granitic and gneissic formations. Amorphous silica-rich solutions circulating through fractures and cavities in these rocks led to the secondary deposition of non-precious opal, primarily occurring as the clear, glass-like variety known as hyalite or amorphous network silica. While the region was never a major site for commercial opal mining, the area gained interest among mineral collectors in the mid-to-late twentieth century, particularly during local construction projects, road excavations, and rock outcrops that briefly exposed collector-quality, botryoidal coatings and crusts of hyalite opal on host rock.
Product details
SpeciesOpal
SizeSmall Cabinet
Dimensions8.0 x 7.0 x 1.5 cm
Added on10/14/2026
LocalityWhite Oak, Montgomery Co., Maryland, USA
Current owner
Unknown Owner
- Acquired
- Oct 2026
- Price paid
- $125.00
Previous owners
| Date | Collector | Acquisition price |
|---|---|---|
| — | Weinrich Minerals | Not disclosed |
Comments