75 grams of quinoa (dry) is 2.65 oz (75 g) in weight, which fills a volume of 6.34 tbsp (93.8 mL). When poured into a loose pile, it is about half the size of a tennis ball.

In kitchen measures
6.34 tablespoons
19 tsp · 6.34 tbsp · 0.396 cups
about half the size of a tennis ball
Quinoa (dry) typically ranges 0.75–0.85 g/mL depending on how it's packed. A firmly packed scoop weighs more.