The dilution factor is 10.
In your example,
You have diluted the sample by a factor of 10.
The dilution factor is often used as the denominator of a fraction. For example, a DF of 10 means a 1:10 dilution.
Here, the sample is not liquid. But it is generally agreed that 1 g of sample has a volume of 1 mL, even if that is not actually the case. You still get convenience and reproducibility.