Lieutenant Colonel insignia is identified by a Silver Maple Leaf.
In the US Army it is a cluster of silver OAK leaves.
In the British army it is a crown and a single 'pip'.
Lieutenants in the US Military have two rank insignia coorelating to their paygrade. O-1, 2nd lieutenant rank insignia is brass or yellow. O-2, 1st Lieutenant rank insignia is silver/chrome.
Very basically speaking, the difference is one step in rank. While a Lt. Colonel is normally referred to a Colonel, a Colonel is sometimes to referred to as a "full bird colonel" to distinguish the difference. In the Army at least, a Lt. Colonel wears a clover leaf rank insignia (silver, I think) but a full Colonel wears an eagle insignia, hence the reference "full bird."
Lieutenant Colonel, the insignia is a silver oak leaf.
Lieutenant Colonel.
An officer in the United States Army who wears a silver eagle is typically a Colonel, which is a rank above Lieutenant Colonel and below Brigadier General. The silver eagle is worn on their collar insignia denoting their rank.
Lieutenant Commander
US Colonels don't wear stripes. A Lieutenant Colonel wears a silver oak leaf, and a full colonel wears an eagle. Stripes are worn by enlisted personnel, and not by commissioned officers, save for on naval shoulder boards. See related links "US Military Enlisted Rank Insignia Chart" and "US Military Commissioned Officer Rank Insignia Chart".
Jeff Cooper was a lieutenant colonel in the Marine Corps.
A silver colored Eagle with both of his wings fully extended. This is also the insignia of a US Navy Captain. A USN Captain is the same as a USA Colonel. Not to be confused with a USA Captain, which in the USN is a Lieutenant (two silver bars attached together).
Lieutenant Colonel (LTC) is a higher rank than 1st Lieutenant (1LT). LTC is a fairly senior rank, while 1LT is a junior officer. In the US Army, (commissioned) officer ranks from lowest to highest are: Second Lieutenant First Lieutenant Captain Major Lieutenant Colonel Colonel Brigadier General Major General Lieutenant General General General of the Army (AKA "five star general" - this rank was only awarded to WWII era generals like MacArthur and Eisenhower) In the US Army, junior officers (Second Lieutenant - Captain) are referred to as company grade officers, while Majors-Colonels are referred to as field grade. General officers are also known as "flag officers" because they're entitled to fly a personal flag with their rank insignia on it.
A Major is an Commissioned Officer is the military where as a Sergeant is an Non-Commissioned Officer (NCO). So yes a Major is higher in rank than a Sergeant.
Lieutenant colonel
It could be the rank of Lieutenant Colonel.