Close .. sounds close to passing. When it goes into the bladder it is usually pretty much a non-event as long as it can get out ok. I have gotten the black stuff too .. I call it "pepper flakes" but it can actually be dried blood and/or debris from the kidney itself. I have had some analyzed and it comes back as "debris".
No, stones are not always round and that is the problem! I have had a fishook on a 1.0mm stone get stuck and it hurt awfully bad.
They are jagged oftentimes.
Mine are calcium oxalate.
Renal calculi can vary in size from as small as grains of sand to as large as a golf ball. Kidney stones typically leave the body by passage in the urine stream, and many stones are formed and passed without causing symptoms.
The resulting obstruction with dilation or stretching of the upper ureter and renal pelvis as well as spasm of muscle, trying to move the stone, can cause severe episodic pain, most commonly felt in the flank, lower abdomen and groin (a condition called renal colic). Renal colic can be associated with nausea and vomiting.
Damage to the lining of the urinary tract cancause discoloration of urine.
In most cases, a smaller stone that is not symptomatic is often given up to four weeks to move or pass before consideration is given to any surgical intervention .