Any thoughts on using lime stone sand in cob? The gentleman at the quarry said it has a higher refractory temperature than silica based sands.
"Let him who possesses a field, so partake of its yearly fruits, that he may not suffer the ground to be injured by his negligence; but let him endeavor to hand it down to posterity as he received it, or even better cultivated. Let him so feed on its fruits that he neither dissipates it by luxury, nor permits to be marred or ruined by neglect."
Hmmm...refractory being higher than silica...that raises questions.
Dolomitic limestone may have a hire quartz, silicate and chert content but to call it "refractory" would be pushing it. I don't believe any limestone species has a higher refractory capacity than silicates especially albumin silicate. I would ask more questions.
As for its use as an additive to cobb...I see no issue at all.