The mintage of the Proof 1870 Quarter Dollar is listed at 1,000 pieces, which represents the number of coins struck, but not necessarily sold. In the 1870's, proof mintages were based on both anticipated and actual demand, either of which rarely matched exactly. If there was a difference, it must have been small, because the 1870 Proof Quarter is common.
The majority of the examples certified by PCGS are of the non-Cameo version, but this number includes some Cameo examples which were certified before PCGS began recognizing the Cameo designation. In actuality, Cameos represent perhaps fifty percent of this date, with Deep Cameos making up a much smaller percentage.
Gem 1870 Quarters are somewhat scarce, indicating poor storage techniques. The finest 1870 Quarter certified by PCGS is a single, nion-Cameo PR67.