Taking Rocks for Granite: An Integrated Geological, Mineralogical, and Textural Study of Curling Stones Used in International Competition
Bibliographic record
Abstract
ABSTRACT The duopoly of curling stone sources suitable for international competition (Ailsa Craig, Firth of Clyde, Scotland and Trefor, Llŷn Peninsula, North Wales) has led to a long-held paradigm that the rocks from these localities are geologically unique. To evaluate this paradigm, we provide the first comprehensive, detailed analyses of the geological, mineralogical, and textural properties of curling stones, with a focus on three main areas: (1) the collective features of all curling stone lithologies, (2) the differences among the lithologies used for running bands versus striking bands, and (3) the presence of quartz, whose brittleness was previously considered to be undesirable in curling stones. The four curling stone varieties from the two localities (Ailsa Craig Blue Hone, Ailsa Craig Common Green, Blue Trefor, and Red Trefor) were analyzed using petrography, scanning electron microscopy, digital image analysis, powder X-ray diffraction, and normative mineralogy, with the following results: The curling stone varieties that are suitable for international competition can be broadly characterized as fine- to medium-grained, sparsely porphyritic to glomeroporphyritic, weakly to moderately altered, massive to weakly foliated, Phanerozoic granitoids (sensu lato). All four varieties are composed of feldspar (65–80 mod.%, with albite being the dominant component) and quartz (15–25 mod.%), along with mafic and accessory minerals (5–20 mod.%). The Ailsa Craig suite is classified as alkali feldspar quartz syenite, whereas the Trefor suite ranges from quartz monzogabbro (Blue Trefor) to granodiorite-granite (Red Trefor). None are strictly classified as granite.Predominantly equigranular textures are preferred for running bands (Ailsa Craig Blue Hone), whereas seriate to glomeroporphyritic textures are preferred for striking bands (Ailsa Craig Common Green, Blue Trefor, and Red Trefor). These are consistent with observations of used curling stones: pitting adversely affects larger grains in the running band, whereas a wider grain-size distribution correlates with fewer crescent-shaped fractures in the striking band.The appreciable abundance of unstrained, interstitial quartz (15–25 mod.%) in all curling stone samples challenges the longstanding belief of its absence and undesirability in curling stones. The degree of strain in quartz is likely to be a key criterion for selecting prospective curling stone materials. In conclusion, none of the examined characteristics of curling stones are unique in comparison to granitoids worldwide.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.005 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".