How to differentiate between unoaked sec Chenin Blanc from Touraine and Chablis?

Hi, I just did over weekend double blind tasting and confused unoaked dry Chenin Blanc from Touraine (Loire Valley) with Chablis. Any suggestions for what to pay attention next time when identifying these wines? They have very similar structure profile: Medium(+) Acidity, Medium Alcohol. Generally I would think that minerality would be differentiator, but this Chenin Blanc had quite pronounced nose of crushed white stones and chalk. The only think I believe should point me to Chenin was medium straw color instead of pale straw. Really would appreciate any additional suggestions for what to pay attention next time. Thanks