Is this vase watertight for fresh flowers?

The listing does not state whether the inside is glazed or sealed. If you plan to use fresh water, line it with a glass or plastic insert or test it first.

How tall is it, and what fits inside?

It stands about 12 inches tall and 5 inches wide. That suits long stems, branches and tall dried arrangements better than wide bouquets.

Is it heavy enough to stay upright?

It is ceramic, so it has more weight than glass or plastic of the same size. A tall arrangement can still make it top-heavy, so keep it out of walkways.

Does the gold run all the way around?

The gold is an accent on a white body. Placement varies by piece, so check the vase in person if the pattern matters to you.

Can it be used outdoors?

It is a ceramic indoor decorative vase. Freezing temperatures and constant moisture can crack or craze the finish, so keep it indoors or on a covered porch.