The package below are uncooked tapioca pearls in a rectangular rough surface package. It is as hard as rock and would cause a severe injury when thrown against enemy. The vacuum packing compressed it, making it hard. It is not surprising, even a powdered milk will be as hard if packaged in the same manner.
Tapioca pearls are sago in Tagalog. The soft chewy balls in samalamig and other icy drinks, e.g. Zagu. However, referring tapioca pearls as sago is a misconception.
Sago and tapioca are two different things. The first is a starch extracted from the spongy center or pith of various tropical palm stems (ubod in Tagalog), such as Metroxylon sagu. The latter is a starch derived from cassava. Pearls are produce by passing the starch through sieve under pressure.
The first is referred as sago while the latter is tapioca pearls and sometimes as pearl sago. Both closely resemble each other. Typically round, small, dry and opaque. Maybe white or colored naturally grey, brown or black, or artificially pink, yellow, green, etc. When soaked and cooked, both become much larger, translucent, soft and spongy.
Confusion between the two is unavoidable since the only difference is the starch source. I am not sure which is more prevalent in our market. Perhaps the tapioca pearls. Cassava is a lot easier to produce than palm.