The present invention relates in particular to a mixture comprising or at least essentially consisting of compound of formula (Ia) and (beta,beta-(4aR,5R,7aS,9R)-octahydro-2,2,5,8,8,9a-hexamethyl-4H-4a,9-methanoazuleno(5,6-d)-1,3-dioxole) of the formula (Ib), wherein the weight ratio of the compound of the formula (Ia) to the compound of the formula (Ib) in the mixture is in the range from 90:10 to 99:1. The present invention further relates to a method for producing such a mixture, to new odorant and/or aroma substance compositions, and to the use of a mixture of the invention (a) for masking or diminishing the one or more unpleasant olfactory impressions of one or more unpleasantly smelling substances, and/or (b) for intensifying the one or more pleasant olfactory impressions of one or more pleasantly smelling substances.