The Medal of the Immaculate Conception is more popularly known as the Miraculous Medal. On the front of the Miraculous Medal Mary is standing upon a globe, crushing the head of a serpent beneath her foot. She stands upon the globe, as the Queen of Heaven and Earth (Rev 12). Her foot crushes the serpent to proclaim Satan and all his followers are helpless before her (Gn 3:15).

This is very poinient to me because this past Christmas I gave all my nieces and nephews a copy of the Douay-Rheims Bible. This is poinient because only in the Douay-Rheims Bible does Genesis 3:15 say the serpent will "lie in wait for her heel". All other versions including Catholic versions say that the serpent will strike back, not just lie in wait for her heel. This is a good time to note that the Douay-Rheims Bible was the first English Catholic translation of the Latin Vulgate.

Also on the front of the medal Mary's arms are outstretched with rays of light streaming from her fingers. Below the figure of Mary is the year 1830 which has to do with the history of this medal as I mention below. Framing the figure of Mary is the inscription, usually in Latin "O Mary, conceived without sin, pray for us who have recourse to thee."

On the back of the medal twelve stars (Rev 12) encircle a large M with a cross above it. Below this are two hearts with flames arising from them. One heart is encircled in thorns (the Sacred Heart of Jesus) and the other heart is pierced by a sword (the Immaculate Heart of Mary). The bar under the cross is a sign of the earth.

The M stands for Mary and the interweaving of her initial and the cross show Mary’s close involvement with Jesus and our world. This shows Mary’s part in our salvation and her role as mother of the Church.  No human being has played or is playing a greater role in God's plan than Mary.

Here's an image of the medal in gold.

The history of the Miraculous Medal starts in July of 1830 when Mary appears to Catherine Labouré, a nun of the Daughters of Charity in Paris. At this time Mary said to Catherine, “My child, I am going to give you a mission". In November of 1830 Catherine sees a vision of Mary while in meditation which turns out to be what is on the medal. During the third appearance of Mary to Catherine Mary said “Have a medal struck upon this model. Those who wear it will receive great graces, especially if they wear it around the neck.”

With approval of the Church, the first Medals were made in 1832 and were distributed in Paris. Almost immediately the blessings that Mary had promised began to shower down on those who wore her Medal. Stories of grace and health, peace and prosperity, followed those who wore the Medal. Before long people were calling it the “Miraculous” Medal.

You can get this medal for free, whether you are Catholic or not from the Association of the Miraculous Medal. The Association has a more detailed history of the Medal. The Catholic Encyclopedia also has a good article on the Miraculous Medal.

God bless
Mike