Contract mechanics
A standard gold lot typically represents 100 ounces, so a one dollar move in the quote is worth about 100 units of the account currency per lot. That is many times the per-pip value of a standard FX lot.
Because of this, gold positions should usually be sized in fractions of a lot, not whole lots.
Volatility profile
Daily ranges of 15 to 30 dollars are common and can extend far beyond that around US inflation data and central bank decisions. Stops placed at FX-sized distances get taken out by ordinary noise.
What drives the price
Real interest rates, the US dollar, and safe-haven demand. Gold tends to strengthen when real yields fall and when geopolitical or financial stress rises.
Costs
Spreads widen noticeably outside the London and New York sessions, and swap on gold is often materially negative on the long side. Multi-week gold positions need the swap figure checked before entry.