It's about as heavy as a Poppy Seed.
It's about half as heavy as a Grain of Sugar.
In other words, 300,000 nanograms is 0.48 times the weight of a Grain of Sugar, and the weight of a Grain of Sugar is 2.08 times that amount.(a.k.a. white sugar, a.k.a. white refined sugar, a.k.a. table sugar, a.k.a. sucrose, a.k.a. saccharose)
It's about five times as heavy as a Grain of Salt.
In other words, 300,000 nanograms is 5.13 times the weight of a Grain of Salt, and the weight of a Grain of Salt is 0.195 times that amount.
It's about one-tenth as heavy as a Sesame Seed.
In other words, 300,000 nanograms is 0.0824 times the weight of a Sesame Seed, and the weight of a Sesame Seed is 12.1 times that amount.(Sesamum indicum)
A sesame seed weighs approximately 3,640,000 nanograms. The McDonald's Big Mac sandwich, which is well-known for its sesame seed top bun, accounts for the consumption of an estimated 2,010,000,000,000,000.0 nanograms of sesame seeds each day.
It's about one-fifteenth as heavy as a Grain of Sand.
In other words, the weight of a Grain of Sand is 15 times 300,000 nanograms.(medium grain)
With tremendous variety in the size of grain and the component material, grains of sand weigh an average of 4,400,000 nanograms. In 2007, a team of seven in Myrtle Beach created the world's tallest sandcastle, which measured 15.10 m (49.55 ft) in height.
It's about one-one-hundredth as heavy as a Grain of Rice.
In other words, the weight of a Grain of Rice is 100 times 300,000 nanograms.(long grain; 14% moisture content)
A single long grain of rice weighs an average of 29,000,000 nanograms. A staple through most of human history, archaeological evidence indicates that the earliest rice cultivation was about 11,500 years ago.
It's about one-five-hundredth as heavy as a Raindrop.
In other words, the weight of a Raindrop is 500 times 300,000 nanograms.(a.k.a. drop, a.k.a. droplet) (average)