Chromium tanning has long been known to produce the best tanned cowhide rug. A properly chromium tanned cow hide will last much longer than a cowhide rug tanned with a different process. Chromium tanning is extremely high tech and expensive. As a result, most countries do not tan their cow hides this way. Even when a chromium tanning process is used on a cowhide rug, often times the results are unsatisfactory since it is such a difficult process as compared to more conventional forms of tanning.