What is the ruling regarding equality (tamathul) in exchanges involving items whose exchange involves prohibition of excess (riba)?

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There is consensus among scholars, held by Abu Hanifa and Al-Shafi'i, that equality must be established in exchanges where excess is prohibited. For items measured by volume (kayl), equality is determined by volume, and for items weighed (mawzunat), equality is determined by weight. If this equality is confirmed, differences in other aspects are disregarded. The evidence is the Prophet's saying concerning gold, silver, wheat, and barley, commanding equality in weight or measure: 'Gold for gold, weight for weight; silver for silver, weight for weight; wheat for wheat, measure for measure; and barley for barley, measure for measure. Whoever gives more or asks for more has engaged in usury.' This applies to all weighed goods by analogy to gold and silver.