Seed malas are the most common mala used in Tibet and Nepal.  Seeds are sustainable and are harvested each year then drilled and made into mala beads.  In the past few years Bodhi seeds in this 8mm size have become impossible to get, I saw prices in Nepal of over $100 this year.  Raktu beads are much smaller then our Bodhi seed malas and priced much more affordably.  

8mm beads 32 inches around