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Petersburg, Va. Entrance to Mine in Fort Mahone, Intended to Undermine Fort Sedgwick (U.S. Civil War) Color Changing Coffee Mug 11oz

Petersburg, Va. Entrance to Mine in Fort Mahone, Intended to Undermine Fort Sedgwick (U.S. Civil War) Color Changing Coffee Mug 11oz

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Regular price $19.99 USD
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Petersburg, Va. Entrance to Mine in Fort Mahone (U.S. Civil War) This historical site refers to an entrance to a mine located in Fort Mahone during the American Civil War, situated in Petersburg, Virginia. The mine was constructed as part of Union forces' efforts to undermine Fort Sedgwick, a Confederate fortification. This strategic maneuver aimed at weakening the defensive line held by Confederate troops and eventually capturing the city of Petersburg, an important supply center for the Confederacy. Despite numerous attempts, the mine was not successfully detonated before the end of the war, preserving Fort Sedgwick's integrity. The site is significant in understanding the engineering tactics employed during the American Civil War and the pivotal role of Petersburg in the broader context of the conflict.
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Color-changing ceramic mugs with a glossy finish, black exterior, and white interior. Available in one size: 11 oz (≈330 ml). Heat-reactive coating reveals your custom design when filled with hot liquid. BPA- and lead-free, with a comfortable C-handle.

This mug brings a playful twist to the daily coffee or tea ritual. At room temperature, it looks like a simple black mug with a glossy finish. But add a hot beverage, and your chosen design fades into view, showing vivid colors against the white interior.

The ceramic body is durable enough for repeated use, while the C-shaped handle balances comfort and grip. Printing uses sublimation techniques that fuse color into the heat-reactive surface for crisp results when the design appears.

  • Material: ceramic with glossy black exterior and white interior.
  • Size: one standard size, 11 oz (≈330 ml).
  • Finish: glossy glaze with heat-sensitive surface.
  • Printing: sublimation process produces crisp, vibrant colors.
  • Safety: BPA-free and lead-free, suitable for everyday drinks.
  • Effect: design is faintly visible when cold, fully revealed when hot.

Perfect as a novelty gift or a fun personal mug, the heat-reactive design makes coffee breaks more engaging. It works well for morning coffee, afternoon tea, or hot chocolate.

  1. Daily routine: fill with any hot beverage to reveal your chosen artwork.
  2. Gifting: the “magic” reveal makes it a memorable present for birthdays, holidays, or office exchanges.
  3. Office use: sparks conversation while still being practical for everyday drinks.

Note: for best results, avoid designs that rely heavily on deep black backgrounds, as they may blend with the mug’s surface when cold.

Unlike standard mugs, color-changing mugs require gentler care to preserve the heat-reactive coating. Hand-wash only — avoid the dishwasher and abrasive scrubbers, which can damage the finish and reduce the effect.

The mug is safe for short microwave use when heating liquids, but repeated high-heat cycles may shorten the lifespan of the coating. Always allow the mug to cool before washing.

Available in one classic size: 11 oz (approximately 330 ml). It’s large enough for most standard coffee makers and fits comfortably in most cabinets.

Size guide

All measurements are product dimensions in inches.

11 oz
Height (in) 3.78
Diameter (in) 3.23
Diameter w/ handle (in) 4.76

Note: measurements are approximate; slight variations may occur due to manufacturing tolerances.