W011 / Montana, Wyoming
Dryhead agate
Agate; sedimentary-hosted chalcedony
Warm-colored bands and pale silica can make an attractive comparison candidate, but they are not a locality fingerprint.
← Western Lapidary Materials
Robert M. Lavinsky / iRocks · CC BY-SA 3.0 · No changes
Source-labelled comparison, not independently authenticated deposit
What it is
Agate; sedimentary-hosted chalcedony
What to look for
Warm-colored bands and pale silica can make an attractive comparison candidate, but they are not a locality fingerprint.
At the cutting bench
Inspect the actual piece for fractures, voids and cutting orientation. Deposit-specific yield and polish data are UNKNOWN.
Under the loupe
Historical labels include Montana and Wyoming. Preserve the exact label instead of silently moving every piece to one modern mine attribution.
Source & collecting access
The technical paper is formation evidence, not evidence of current production, a closed mine or a permitted collecting site.
Status checked 2026-10-01The market notebook
UNKNOWN — no verified completed-sales sample sufficient for a range
Market researched 2026-10-01Open the field notes
Color comparison tags
Orange, Yellow, Pink, Brown/Tan, White/Cream/Clear
Geology & evidence limits
The 2009 technical study concerns sedimentary-hosted agates in the Dryhead area of Montana and supports a hydrothermal contribution to their formation.
Collecting & trade history
The technical paper is formation evidence, not evidence of current production, a closed mine or a permitted collecting site.
Reading old-stock material
Preserve the estate label, wrapping, purchase record and associated pieces. Old-stock status alone does not authenticate origin or imply a premium.
What we know—and what we don’t
Visual resemblance is a comparison clue, not proof of material identity, locality or documented provenance. Keep source labels and estate records separate from your visual assessment.
C&C Reference Collection
Reference examples are source-labelled and do not authenticate the locality of an unlabelled specimen.
Sources & Further Reading
- Dryhead agate research, DOI 10.1180/minmag.2009.073.4.673
2009 technical paper; abstract/metadata reviewed, full text not claimed
- University of Nebraska–Lincoln historical agate database
Historical specimen-label/bibliography evidence; not current access or image permission
Cut and polish with appropriate wet methods and silica-dust controls. Historic directions and mine names are not current permission to collect.